`100 g` of `NaCl` is stirred in `100 mL` of water at `20^(@)C` till the equilibrium is attained:
(`a`) How much `NaCl` goes into the solution and how much of it is left undissolved at equilibrium? The solubility of `NaCl` at `20^(@)C` is `6.15 mol//litre`.
(`b`) What will be the amount of `NaCl` left undissolved, if the solution is diluted to `200 mL`?

Explanation

Solubility of `NaCl=6.15mol//litre`
`=6.15xx58.5g//litre`
`=(6.15xx58.5)/(10)g//100mL`
`=36g//100mL`
(`a`) Thus amount of `NaCl` in `100mL` at `20^(@)C` get dissolved `=36g`
and amount of `NaCl` in `100mL` at `20^(@)C` remained undissolved `=100-36=64g`
(`b`) If volume of solution is diluted to `200mL`, `36g` more of `NaCl` will be dissolved leaving only `28g NaCl` dissolved in `200 mL`.