What weight of NaCl is needed to make 2.0 dm³ of a 1.5M solution? [Na = 23, Cl = 35.5]

A. 116 g
B. 175 g
C. 87 g
D. 58 g

Correct Answer:

Option B – 175 g

Explanation

Molar mass of Nacl = 23 + 35.5 = 58.5 g/mol
Number of moles of Nacl = conc. in mol/dm³ X vol. in dm³
= 1.5 X 2.0 = 3.0 moles
1 mole of NaCl has a weight of 58.5 X 3 = 175.5g