Question

A $1000$ g sample of $NaOH$ contains $3$ moles of $O$ atom, what is the purity of $NaOH$?

• A. $14\%$
• B. $100\%$
• C. $12\%$
• D. $24\%$

Answer 1

Answer: (C)

$12\%$

A $1000$ g sample of $NaOH$ contains $3$ moles of $O$ atoms which corresponds to $3$ moles of $NaOH$.

The molar mass of $NaOH$ is $40$ g/mol.

$3$ moles of $NaOH$ weigh $3\times 40=120$ g.

Therefore, the purity of $NaOH$ is $\frac{120}{1000}\times 100=12$%

Hence, the correct option is $C$