Question

A 5% solution of sugarcane (mol.wt.$=342$) is isotoinc with $1$% solution of $X$ under similar conditions. The mol.wt of $X$ is

• A. $136.2$
• B. $68.4$
• C. $34.2$
• D. $171.2$

Answer 1

The correct option is B $68.4$

${\pi }_{sugarcane}={\pi }_X$
$C_{sugarcane}=C_X$
${\left(\frac{w_B\times 1000}{m_B\times V}\right)}_{sugarcane}={\left(\frac{w_B\times 1000}{m_B\times V}\right)}_X$
${\left(\frac{5\times 1000}{342\times V}\right)}_{sugarcane}={\left(\frac{1\times 1000}{m_B\times V}\right)}_X$
$m_B$ of $X=\frac{1000\times 1000\times 342}{5\times 1000\times 100}=68.4$