JEE Mains · Chemistry · STD 11 - 1. Some basic concept of chemistry
Molality (m) of \(3 \mathrm{M}\) aqueous solution of \(\mathrm{NaCl}\) is _______. (Given : Density of solution \(=1.25 \mathrm{~g} \mathrm{~mL}^{-1}\), Molar mass in \(\left.\mathrm{g} \mathrm{mol}^{-1}: \mathrm{Na}-23, \mathrm{Cl}-35.5\right)\)
- A \(2.90 \mathrm{~m}\)
- B \(2.79 \mathrm{~m}\)
- C \(1.90 \mathrm{~m}\)
- D \(3.85 \mathrm{~m}\)
Answer & Solution
Correct Answer
(B) \(2.79 \mathrm{~m}\)
Step-by-step Solution
Detailed explanation
\(3\) moles are present in \(1\) litre solution \(\text { molality }=\frac{3 \times 1000}{1.25 \times 1000-[3 \times 58.5]}=2.79 \mathrm{~m}\)
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