question_answer 63)

  Which of the following solutions have the same concentration? (a) 20 g of \[NaOH\] in 200 mL of solution (b) 0.5 mol of in 200 mL of solution (c) 40 g of\[NaOH\]  in 100 mL of solution (d) 20 g of \[KOH\] in 200 mL of solution              

Answer:

  (a, b) (a) \[{{M}_{NaOH}}=\frac{{{w}_{B}}\times 1000}{{{m}_{B}}\times V}=\frac{20\times 1000}{40\times 1000}=2.5\,mol\,{{L}^{-1}}\] (b)  \[{{M}_{KCl}}=\frac{n}{V}\times 1000=\frac{0.5}{200}\times 1000=2.5mol\,{{L}^{-1}}\] (c)  \[{{M}_{NaOH}}\frac{{{w}_{B}}\times 1000}{{{m}_{B}}\times V}=\frac{40\times 1000}{40\times 100}=10\,mol\,{{L}^{-1}}\] (d)  \[{{M}_{KOH}}=\frac{{{w}_{B}}\times 1000}{{{m}_{B}}\times V}=\frac{20\times 1000}{56\times 200}-1.785mol\,{{L}^{-1}}\]