Question

How many grams of commercial sodium hydroxide containing 75% $N{a}_{2}O$ are required to prepare 600 g of a 15% sol. of $NaOH$?

• A. 56
• B. 93
• C. 34
• D. 87

Answer 1

The correct option is B 93

Let $x$ $gm$ of $N{a}_{2}O$ are there.

Pure $N{a}_{2}O\Rightarrow x\times \frac{75}{100}=\frac{3x}{4}$

Pure $NaOH=600\times \frac{15}{100}=90$ $gm$

Moles $=\frac{90}{40}=2.25$ $moles$

$N{a}_{2}O+H_{2}O⟶2NaOH$

$1.125$ $moles$ $2.25$ $moles$

$\Rightarrow \frac{3x}{4\times 62}=1.125$

$\Rightarrow x=93$ $gm$