Question

Value of $\Lambda_{ m }^{\infty}$ for $SrCl _{2}$ in water at $25^{\circ}$ from the following data :

Conc. (mol/L)	0.25	1
$\Lambda_{ m }\left(\Omega^{-1} cm ^{2} mol ^{-1}\right)$	260	250

• A. 270
• B. 260
• C. 250
• D. 255

Answer 1

Answer: (A)

According to debye huckel onsagar equation
$\Lambda_{ C }=\Lambda_{\infty}- b \sqrt{ C } $
$260=\Lambda_{\infty}- b \sqrt{0.25}$ ... (1)
$250=\Lambda_{\infty}- b \sqrt{1} $ ....(2)
$ eq ^{ n }(1)- eq ^{ n }(2) $
than $ 10-0.5 b $
$ b =20$
on putting value in eq $^{ n }(1)$
$260-\Lambda_{\infty}-20 \times 0.5$
$\Lambda_{\infty}=270$