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Why should magnesium ribbon be cleaned before burning in air ?
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Write the balanced equations
for the following chemical reactions.
(a) Hydrogen + chlorine
hydrogen
chloride
(b) Barium chloride + aluminium
sulphate
barium
sulphate + aluminium chloride
(c) Sodium + water
sodium
hydroxide + hydrogen
-
Write a balanced
chemical equation with state symbols for the following reactions:
(a) Solutions
of barium chloride and sodium sulphate in water react to give insoluble barium sulphate
and the solution of sodium chloride.
(b) Sodium
hydroxide solution (in water) reacts with hydrochloric acid solution (in water)
to produce sodium chloride solution and
water,
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A solution of the substance X is used for white washing.
(i) Name the substance X and write its formula.
(ii) Write the reaction of the substance X with water.
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Why is the amount of gas collected in one of the test tubes in electrolysis of water than the amount collected in the other? Name the gas.
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Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
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Give an example of a double displacement reaction.
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1.
Identify the substances that are oxidized and the substances that
are reduced in the following reactions:
(i)
(ii)
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Which of the statements about the reaction below are incorrect ?
(i)
Lead is getting reduced.
(ii) Carbon dioxide is getting oxidised.
(iii) Carbon is getting oxidised.
(iv)Lead oxide is getting reduced.
(a) (i) and (ii) (b) (i) and (iii) (c) (i), (ii) and (iii) (d) all
-
The
above reaction is an example of a
(a) combination
reaction (b) double displacement
reaction
(c) decomposition reaction (d)
displacement reaction
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What happens when dilute hydrochloric acid is added to iron filings ? Tick the correct answer.
(a) Hydrogen gas and iron chloride are produced.
(b) Chlorine gas and iron hydroxide are produced.
(c) No reaction takes place.
(d) Iron salt and water are produced.
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What is a balanced chemical equation ? Why should chemical equations be balanced ?
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Translate the following statements into chemical equations and then balance them :
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas bums in air to give water and sulphur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
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Balance the following chemical equations :
(a)
(b)
(c)
(d)
-
Write the balanced
chemical equations for the following reactions :
(a) Calcium
hydroxide + Carbon dioxide
Calcium
carbonate + Water
(b) Zinc +
Silver nitrate
Zinc
nitrate + Silver
(c) Aluminium
+ Copper chloride
Aluminium
chloride + Copper
(d) Barium chloride
+ Potassium sulphate
Barium
sulphate + Potassium chloride
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Write the balanced chemical equations for the following and identify the type of reaction in each case.
(a)Potassium bromide
+ Barium iodide
Potassium iodide
+ Barium bromide
(b) Zinc carbonate
Zinc oxide
Carbon dioxide
(c) Hydrogen
Chlorine
Hydrogen chloride
(d) Magnesium
Hydrochloric acid
Magnesium chloride
Hydrogen
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What does one mean by exothermic and endothermic reactions ? Give examples.
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Why is respiration considered as an exothermic reaction ? Explain.
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Why are decomposition reactions called the Opposite of combination reactions? Write equations for these reactions.
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Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
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What is the difference between displacement and double displacement reactions? Write equations for these reactions.
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In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.
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What do you mean by a precipitation reaction? Explain by giving examples.
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Explain the following in terms of gain or loss of oxygen with two examples each.
(i) Oxidation
(ii) Reduction
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A shiny brown coloured element 'X' on heating in air becomes black in colour. Name the element 'X' and the black coloured compound formed.
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Why do we apply paint on iron articles ?
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Oil and fat containing food items are flushed with nitrogen. Why?
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Explain the following terms with an example each :
(a) Corrosion (b) Rancidity
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question_answer29)
Which of the following is not a physical
change?
(a) Boiling of water to give water
vapour (b) Melting of ice to give water
(c) Dissolution of salt in water (d)
Combustion of liquefied petroleum Gas (LPG)
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question_answer30)
The following reaction is an example of
a
(i) displacement reaction
(ii) combination reaction
(iii) redox reaction
(iv) neutralization reaction
(a) 1 and 4 (b)
2 and 3 (c) 1 and 3 (d) 3
and 4
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question_answer31)
Which of the following statements about
the given reaction are correct?
(i) Iron metal is getting oxidized.
(ii) Water is getting reduced.
(iii) Water is acting as reducing agent.
(iv) Water is acting as oxidizing agent.
(a) 1,2 and 3 (b)
3 and 4 (c) 1,2 and 4 (d) 2 and
4
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question_answer32)
Which of the following are exothermic
processes?
(i) Reaction of water with quick lime
(ii) Dilution of an acid
(iii)Evaporation of water
(iv)Sublimation of camphor (crystals)
(a) 1 and 2 (b) 2
and 3 (c) 1 and 4 (d) 3
and 4
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question_answer33)
Three beakers labelled as A, B and C
each containing 25 mL of water were taken. A small amount of
,
anhydrous
and
were
added to the beakers A, B and C respectively. It was observed that there was an
increase in the temperature of the solutions contained in beakers A and B, where
as in case of beaker C, the temperature of the solution falls. Which one of the
following statement(s) is(are) correct?
1.In beakers A and B, exothermic
process has occurred.
2.In beakers A and B, endothermic
process has occurred.
3.In beaker C, exothermic process
has occurred.
4.In beaker C, endothermic
process has occurred.
(a) Only 1 (b)
Only 2 (c) 1 and
4 (d) 2 and 3
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question_answer34)
A dilute ferrous sulphate solution was
gradually added to the beaker containing acidified permanganate solution. The
light purple colour of the solution fades and finally disappears. Which of the
following is the correct explanation for the observation?
(a) 
is
an oxidising agent, it oxidises
(b)
acts
as an oxidising agent and oxidises
(c) The colour disappears due to
dilution, no reaction is involved
(d) is
an unstable compound and decomposes in the presence ofto
a colourless compound
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question_answer35)
Which among the following is (are)
double displacement reaction(s)?
(i) 
(ii) 
(iii) 
(iv)
(i) and (iv) (b)
Only (ii) (c) (i) and (ii) (d) (iii)
and (iv)
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question_answer36)
Which among the following statement(s)
is/are true? Exposure of silver chloride to sunlight for a long duration turns
grey due to
(i) the formation of silver by
decomposition of silver chloride.
(ii) sublimation of silver chloride.
(iii) decomposition of chlorine gas from
silver chloride.
(iv) oxidation of silver chloride.
(a) (i) Only (b)
(i) and (iii) (c) (ii) and (iii) (d)
Only (iv)
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question_answer37)
Solid calcium oxide reacts vigorously
with water to form calcium hydroxide companied by liberation of heat. This
process is called slaking of lime. Calcium hydroxide dissolves in water to form
its solution called limewater. Which among the following is are true about
slaking of lime and the solution formed?
(i) It is an endothermic reaction.
(ii) It is exothermic reaction.
(iii)The pH of the resulting solution
will be more than seven.
(iv) The pH of the resulting solution
will be less than seven.
(a) (i) and (ii) (b)
(ii) and (iii) (c) (i) and (iv) (d)
(iii) and (iv)
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question_answer38)
Barium chloride on reacting with
ammonium sulphate forms barium sulphate and ammonium chloride. Which of the
following correctly represents the type of the reaction involved?
(i) Displacement reaction
(ii) Precipitation reaction
(iii) Combination reaction
(iv) Double displacement reaction
(a) Only (i) (b)
Only (ii) (c) Only(iv) (d)
(ii) and (iv)
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question_answer39)
Electrolysis of water is a decomposition
reaction. The mole ratio of hydrogen and oxygen gases liberated during
electrolysis of water is
(a) 1 : 1 (b)
2 : 1 (c) 4 : 1 (d)
1 : 2
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question_answer40)
Which of the following is(are) an
endothermic process(es)?
(i) Dilution of sulphuric add
(ii) Sublimation of dry ice
(iii) Condensation of water vapours
(iv) Evaporation of water
(a) Both (i) and (iii) (b) Only
(ii) (c) Only (iii) (d) Both
(ii) and (iv)
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question_answer41)
In the double displacement reaction
between aqueous potassium iodide and aqueous lead nitrate, a yellow precipitate
of lead iodide is formed. While performing the activity if lead nitrate is not
available, which of the following can be used in place of lead nitrate?
(a) Lead sulphate (insoluble) (b)
Lead acetate
(c) Ammonium nitrate (d)
Potassium sulphate
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question_answer42)
Which of the following gases can be used
for storage of fresh sample of an oil for a long time?
(a) Carbon dioxide or oxygen
(b) Nitrogen or oxygen
(c) Carbon dioxide or helium
(d) Helium or nitrogen
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question_answer43)
The following reaction is used for the
preparation of oxygen gas in the laboratory
Which of the following statement(s)
is/are correct about the reaction?
(i) It is a decomposition reaction and endothermic
in nature
(ii) It is a combination reaction
(iii) It is a decomposition reaction and
accompanied by release of heat
(iv)It is a photochemical decomposition
reaction and exothermic in nature
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question_answer44)
Which one of the following processes
involve chemical reactions?
(a) Storing of oxygen gas under pressure
in a gas cylinder
(b) Liquefaction of air
(c) Keeping petrol in a China dish in
the open
(d) Heating copper wire in the presence
of air at high temperature
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question_answer45)
In which of the following chemical
equations, the abbreviations represent the correct states of the reactants and
products involved at reaction temperature?
(a)
(b)
(c)
(d)
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question_answer46)
Which of the following are combination
reactions?
(i)
(ii)
(iii)
(iv)
(a) Both (i) and
(iii) (b) Both (iii) and
(iv)
(c) Both (ii) and
(iv) (d) Both (ii) and
(iii)
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question_answer47)
Write the balanced chemical equations
for the following reactions and identify the type of reaction in each case.
(i) Nitrogen gas is treated with
hydrogen gas in the presence of a catalyst at 773 K to form ammonia gas.
(ii) Sodium hydroxide solution is
treated with acetic acid to form sodium acetate and water.
(iii) Ethanol is warmed with ethanoic
acid to form ethyl acetate in the presence of concentrated
.
(iv) Ethane is burnt in the presence of
oxygen to form carbon dioxide, water and releases heat and light.
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question_answer48)
Write the balanced chemical equation for
the following reactions and identify the type of reaction in each case.
(i) In Thermite reaction, iron (III)
oxide reacts with aluminium and gives molten iron and aluminium oxide.
(ii) Magnesium ribbon is burnt in an
atmosphere of nitrogen gas to form solid magnesium nitride.
(iii) Chlorine gas is passed in an
aqueous potassium iodide solution to form potassium chloride solution and solid
iodine.
(iv) Ethanol is burnt in air to form
carbon dioxide, water and releases heat..
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question_answer49)
Complete the missing
components/variables given as X and Y in the following.
(a)
(b)
(c)
(d)
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question_answer50)
Which among the following changes are
exothermic or endothermic in nature?
(i) Decomposition of ferrous sulphate
(ii) Dilution of sulphuric acid
(iii)Dissolution of sodium hydroxide in
water
(iv) Dissolution of ammonium chloride in
water
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question_answer51)
Identify the reducing agent in the following
reactions.
(a) 
(b)
(c) 
(d) 
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question_answer52)
Identify the oxidizing agent (oxidant)
in the following reactions.
(a)
(b)
(c)
(d)
(e)
(f)
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question_answer53)
Write the balanced chemical equations
for the following reactions.
(a) Sodium carbonate on reaction with
hydrochloric acid in equal molar concentrations gives sodium chloride and
sodium hydrogen carbonate.
(b) Sodium hydrogen carbonate on
reaction with hydrochloric acid gives sodium chloride, water and liberates
carbon dioxide.
(c) Copper sulphate on treatment with
potassium iodide precipitates cuprous iodide (
),
liberates iodine gas and also forms potassium sulphate.
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question_answer54)
A solution of potassium chloride when
mixed with silver nitrate solution, an insoluble white substance is formed.
Write the chemical reaction involved and also mention the type of the chemical
reaction.
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question_answer55)
Ferrous sulphate decomposes with the
evolution of a gas having a characteristic odour of burning sulphur. Write the
chemical reaction involved and identify the type of reaction.
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question_answer56)
Why do fire flies glow at night?
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question_answer57)
Grapes hanging on the plant do not
ferment but after being plucked from the plant can be fermented. Under what
conditions do these grapes ferment? Is it a chemical or a physical change?
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question_answer58)
Which among the following are physical
or chemical changes?
(a) Evaporation of petrol
(b) Burning of Liquefied Petroleum Gas
(LPG)
(c) Heating of an iron rod to red hot
(d) Curdling of milk
(e) Sublimation of solid ammonium
chloride
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question_answer59)
During the reaction of some metals with
dilute hydrochloric acid, following observations were made.
(a) Silver metal does not show any
change
(b) The temperature of the reaction
mixture rises when aluminium (Al) is added
(c) The reaction of sodium metal is
found to be highly explosive
(d) Some bubbles of a gas are seen when
lead(Pb) is reacted with the acid
Explain these observations giving
suitable reasons.
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question_answer60)
A substance X, which is an oxide of a
group 2 element, is used intensively in the cement industry. This element is
present in bones also. On treatment with water it forms a solution which turns
red litmus blue. Identify X and also write the chemical reactions involved.
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question_answer61)
Write a balanced chemical equation for
each of the following reactions and also classify them.
(a) Lead acetate solution is treated
with dilute hydrochloric acid to form lead chloride and acetic acid solution.
(b) A piece of sodium metal is added to
absolute ethanol to form sodium ethoxide and hydrogen gas.
(c) Iron (III) oxide on heating with
carbon monoxide gas reacts to form solid iron and liberates carbon dioxide gas.
(d) Hydrogen sulphide gas reacts with
oxygen gas to form solid sulphur and liquid water.
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question_answer62)
Why do we store silver chloride in dark
coloured bottles?
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question_answer63)
Balance the following chemical equation
and identify the type of chemical reaction.
(a) 
(b) 
(c) 
(d) 
(e) 
(f)
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question_answer64)
A magnesium ribbon is burnt in oxygen to
give a white compound X accompanied by emission of light. If the burning ribbon
is now placed in an atmosphere of nitrogen, it continues to burn and forms a
compound Y.
(a) Write the chemical formulae of X and
Y.
(b) Write a balanced chemical equation,
when X is dissolved in water.
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question_answer65)
Zinc liberates hydrogen gas when reacted
with dilute hydrochloric acid, whereas copper does not. Explain, why?
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question_answer66)
A silver article generally turns black
when kept in the open for a few days. The article when rubbed with toothpaste
again starts shining.
(a) Why do silver articles turn black
when kept in the open for a few days? Name the phenomenon involved.
(b) Name the black substance formed and give
its chemical formula.
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question_answer67)
On heating blue coloured powder of
copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a
brown gas X is formed.
(a) Write a balanced chemical equation
of the reaction.
(b) Identify the brown gas X evolved.
(c) Identify the type of reaction.
(d) What could be the pH range of
aqueous solution of the gas X?
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question_answer68)
Give the characteristic tests for the
following gases.
(a) CO2 (b)
SO2 (c) O2 (d)
H2
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question_answer69)
What happens when a piece of
(a) zinc metal is added to copper
sulphate solution?
(b) aluminium metal is added to dilute
hydrochloric acid?
(c) silver metal is added to copper
sulphate solution?
Also write the balanced chemical
equation, if reaction occurs.
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question_answer70)
What happens when zinc granules are
treated with dilute solution of 
,
Ha,
HN03, 
and
,
also write the chemical equations, if reaction occurs?
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question_answer71)
On adding a drop of barium chloride
solution to an aqueous solution of sodium sulphite, white precipitate is
obtained.
(a) Write a balanced chemical equation
of the reaction involved.
(b) What other name can be given to this
precipitation reaction?
(c) On adding dilute hydrochloric acid
to the reaction mixture, white precipitate disappears. Why?
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question_answer72)
You are provided with two containers
made up of copper and aluminium. You are also provided with solutions of dilute
HCI, dilute, ZnCl2and H2O. In which of the containers
these solutions can be kept?
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