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JEE Main 20199 AprilEvening Shift

Exam: JEE Main
Year: 2019
Date: 9 April
Shift: Evening Shift
Subject: Chemistry
Chapter: Some Basic Concepts of Chemistry

JEE Main 2019 · 9 April · Evening Shift · Chemistry · Some Basic Concepts of Chemistry

What would be the molality of 20% (mass/mass) aqueous solution of...

What would be the molality of 20% (mass/mass) aqueous solution of

KI

? (molar mass of

KI = 166gmo{l}^{- 1}

)

Options

A $1.35$
B $1.51$
C $1.08$
D $1.48$

Correct answer

B. $1.51$

Step-by-step solution

Molality

= \dfrac{Molesofsolute}{weightofsolvent\left(g\right)} \times 1000

100gm

of solution contains

20gmKI

So, the moles of

KI

= \dfrac{20}{166}

Weight of solvent

= 100 - 20 = 80gm

Molality

= \dfrac{20 \times 1000}{166 \times 80}

= 1.51Molal

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