WCH11 June 2022

4. A solution of sodium chloride, NaCl, is prepared by dissolving 10.0g of the solid in distilled water and making the solution up to 250.0cm3.

What is the concentration of the solution, in moldm−3?

[Mr NaCl = 58.5]

A​​  0.171

B​​  0.684

C​​  10.0

D​​  40.0

ANSWER

B​​  0.684

Analysis of Option/Explanation

Step 1: Calculating Moles by using formula

mole=massvolume

mole=1058.5

=0.1709 mol

Step​​ 2: Calculating concentration by using ration method

0.1709 moles of NaCl  =250cm3

x moles of NaCl=1000cm3

Hence,​​ 

X molesdm3= (1000

=0.69 mol/dm3

Therefore, option B is the correct answer.