Question

A 6.90 M solution of KOH in water contains $30\%$ by mass of KOH. Calculate the density of the solution.

• A. 1.288 $gm{L}^{-1}$
• B. 1.578 $gm{L}^{-1}$
• C. 1.008 $gm{L}^{-1}$
• D. 1.608 $gm{L}^{-1}$

Answer 1

The correct option is A 1.288 $gm{L}^{-1}$

100 g solution contains 30 g KOH

Therefore , $\frac{100}{d}$ mL solution contains $\frac{30}{56}$ mol KOH , d=density in g/m${}^2$

Molarity $=6.90=\frac{30}{56}\times \frac{d}{100}\times 1000$

$d=1.288$ g/mL

Hence, the correct option is $A$