Question

A solution of sodium bicarbonate is prepared by dissolving $60\%$ pure $1.4g$ of sodium bicarbonate in $100mL$ water. The density of the solution is $1.014g/mL$. The correct statement(s) among the following is:

• A. Molarity of the solution is $0.1M$
• B. Molality of the solution is $0.1m$
• C. (w/w)) percentage of sodium bicarbonate solution is less than $0.84\%$
• D. (w/w) percentage of the sodium bicarbonate is $84\%$

Answer 1

Answer: (A), (B), (C)

The correct options are
A Molarity of the solution is $0.1M$
B Molality of the solution is $0.1m$
C (w/w)) percentage of sodium bicarbonate solution is less than $0.84\%$

The sample is $60\%$ pure.
Mass of the sodium bicarbonate = $1.4\times 0.6=0.84g$
Moles of sodium bicarbonate = $\frac{0.84}{84}=0.01mol$
Volume of the solution = $\frac{101.4}{1.014}=100mL$
$Molarity=\frac{0.01}{0.1}=0.1$ M
$Massofthesolvent=100g$
$\therefore Molality=\frac{0.01}{0.1}=0.1$
Percentage mass of the sodium bicarbonate = $\frac{0.84}{101.4}\times 100=0.828\%$