To 5.85gm of Nacl one kg of water is added to prepare of solution. What is the strength of Nacl in this solution (mol. wt. of nacl = 58.5)?
(a) 0.1 Normal (b) 0.1 Molal (c) 0.1 Molar (d) 0.1 Formal
Answer: (b) 5.85 g NaCl = 0.1 mol as it present in 1 kg of water
molality = wt./(m wt. x l) = 5.85/(58.5 x 1) = 0.1 molal