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JEE MainChemistryModeratePhysical Chemistry

Molar conductivity of 0.04 solution at 298 k is 200 Scm2mole-1.
A conductivity cell which is filled with MgCl2 have area of

cross-section of electrode 4cm2 & distance between electrode is 8 cm. If

potential difference between electrode is 10V then find current flow in

miliampere.

Show answer and solution
λm=K×1000M\lambda_{m} = \frac{K \times 1000}{M}
200=K×10000.04200 = \frac{K \times 1000}{0.04}
K=200×0.041000=8×10−3Scm−1K = \frac{200 \times 0.04}{1000} = 8 \times 10^{- 3}S{cm}^{- 1}
K=(l9)×1RK = \left( \frac{\mathcal{l}}{9} \right) \times \frac{1}{R}
8×10−3=[84]×1R8 \times 10^{- 3} = \left\lbrack \frac{8}{4} \right\rbrack \times \frac{1}{R}
R=28×10−3=14×103ΩR = \frac{2}{8 \times 10^{- 3}} = \frac{1}{4} \times 10^{3}\Omega
Again
⇒V=IR\Rightarrow V = IR
So

I=VR=10(14×103)=4×10−2AI = \frac{V}{R} = \frac{10}{\left( \frac{1}{4} \times 10^{3} \right)} = 4 \times 10^{- 2}A

Source: Grass-G / CH-23 Chemistry Paper 31 Dec. FST.docx

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