Question

Coefficient of viscosity $\left(\eta \right)$ is $2.76\times 10$${}^{-4}$ Pa.S at $-40$${}^o$C. If E (for viscosity) is $5984$ J mol${}^{-1}$, calculate $\eta$ at $-{50}^o$C:

• A. $6.17\times 10$${}^{-5}$ Pa.S
• B. $3.17\times 10$${}^{-4}$ Pa.S
• C. $5.19\times 10$${}^{-6}$ Pa.S
• D. $7.10\times 10$${}^{-6}$ Pa.S

Answer 1

Answer: (B)

$3.17\times 10$${}^{-4}$ Pa.S

$\log \eta =\log$ A $+\frac{E}{2.303RT}$
$\log \frac{{\eta }_2}{{\eta }_1}=\frac{E}{2.303R}[\frac{1}{T_2}-\frac{1}{T_1}]$
$\log \frac{{\eta }_2}{2.76\times {10}^{-4}}=\frac{5984}{2.303\times 8.314}[\frac{1}{223}-\frac{1}{233}]$
${\eta }_2=3.17\times {10}^{-4}$ Pa.S