Question

How many grams of nickel (II) chloride hexahydrate are required to prepare 250. mL of aqueous solution whose concentration is 0.255 M? The molar mass of nickel (II) chloride hexahydrate is 237.69 g mol−1.

Answer 1

Answer: 15.2 grams

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute

 $V_s$ = volume of solution in ml

moles of solute (nickel (II) chloride hexahydrate ) =$\farc{\text{given mass}}{\text {Molar mass}}=\frac{xg}{237.69g/mol}$

Putting the values , we get

$0.255= \frac{x\times 1000}{237.69\times 250}$

$x=15.2g$

Thus 15.2 grams of nickel (II) chloride hexahydrate are required to prepare 250. mL of aqueous solution whose concentration is 0.255 M.