question_answer3) A red solid is insoluble in water. However, it becomes soluble if some KI is added to water. Heating the red solid in a test tube results in liberation of some violet coloured fumes and droplets of a metal appear on the cooler parts of the test tube. The red solid is
AIEEE Solved Paper-2003
question_answer6) Ammonia forms the complex ion \[{{[Cu{{(N{{H}_{3}})}_{4}}]}^{2+}}\] with copper ions in the alkaline solutions but not in acidic solutions. What is the reason for it?
AIEEE Solved Paper-2003
A)
In acidic solutions hydration protects copper ions
doneclear
B)
In acidic solutions protons coordinate with ammonia molecules forming \[NH_{4}^{+}\] ions and \[N{{H}_{3}}\] molecules are not available
doneclear
C)
In alkaline solutions insoluble \[Cu{{(OH)}_{2}}\] is precipitated which is soluble in excess of any alkali
question_answer7) The radius of \[L{{a}^{3+}}\] (atomic number of \[La=57\]) is \[1.06\overset{o}{\mathop{A}}\,\]. Which one of the following given values will be closest to the radius of \[L{{u}^{3+}}\] (atomic number of \[Lu=71\])?
AIEEE Solved Paper-2003
question_answer9) For making good quality mirrors, plates of float glass are used. These are obtained by floating molten glass over a liquid metal which does not solidify before glass. The metal used can be
AIEEE Solved Paper-2003