Question

Clauberite is a mineral containing sodium sulphate ($M=142.0$) and calcium sulphate ($M=136$) only. It is the chief source of sodium sulphate, which is used in making glass. If a $20.00g$ sample of glauberite contains $2.88g$ of calcium ($M=40$), what mass of sodium sulphate can be extracted from $1$ ton ($1000kg$) of glauberite?

• A. $102kg$
• B. $511kg$
• C. $710kg$
• D. $855kg$

Answer 1

The correct option is B $511kg$

Given,

Mass of sample=$20.00g$

Mass of Calcium in $20g$ sample=$2.88g$

Now, moles of Calcium in $20g$ sample=$\frac{2.88}{40g/mol}$

$=0.072$ moles

$\therefore$ Number of moles of $CaS{O}_4$ in the given sample=$0.072$ moles

Now, the mass of $CaS{O}_4$ in the given sample=$0.072$ moles $\times 136g/mol$

$=9.792gms$

As it is given only $CaS{O}_4$ & $NaS{O}_4$ is present in sample.

$\therefore$ Mass of $N{a}_{2}S{O}_4$ in the sample=$(20.00-9.792)gms$

$=10.208gms$

Now,

If $20g$ sample contains $10.208gms$ $N{a}_{2}S{O}_4$

$\Rightarrow 1000Kg$ sample contains

$\frac{1000kg\times 10.208g}{20g}=510.4Kg$

$\therefore 510.4Kg\approx 511Kg$ of $N{a}_{2}S{O}_4$ can be extracted