Question

$16.6mg$ of solid silver chromate (molar mass = $332$) when put into $500mL$ water, silver ion and chromate ion are obtained. On adding more solid, the concentration of ions does not increase. If $100mg$ of solid is put into 2 litres of water, then the amount of solid remained undissociated would be :

• A. $33.6mg$
• B. $3.36mg$
• C. $66.4mg$
• D. $6.64mg$

Answer 1

The correct option is A $33.6mg$

16.6 mg of solid silver chromate (molar mass = 332) when put into 500 mL water, silver ion and chromate ion are obtained.
On adding more solid, the concentration of ions does not increase. If 100 mg of solid is put into 2 litre of water, then the amount of solid remained undissociated would be $100\text{mg}-\frac{2000\text{mL}}{500\text{mL}}\times 16.6\text{mg}=33.6\text{mg}$
Note: The solubility of silver chromate is 16.6 mg in 500 mL water.
In 2 L or 2000 mL water, the solubility will be $\frac{2000\text{mL}}{500\text{mL}}\times 16.6\text{mg}$