CUET · CHEMISTRY · PYQ PAPER 2023
2.0 g of benzoic acid dissolved in 25 g of benzene shows a depression in freezing point of 1.62 K. Molal depression constant \(K_f\) of benzene is \(4.9\text{ K kg mol}^{-1}\). What is the percentage association of the acid?
- A \(96.8 \%\)
- B \(46.8 \%\)
- C \(99.2 \%\)
- D \(69.2 \%\)
Answer & Solution
Correct Answer
(C) \(99.2 \%\)
Step-by-step Solution
Detailed explanation
\(m_{\text{obs}} = \frac{\Delta T_f}{K_f} = \frac{1.62 \text{ K}}{4.9 \text{ K kg mol}^{-1}} = 0.3306 \text{ mol kg}^{-1}\) \(M_{\text{benzoic acid}} = 122 \text{ g mol}^{-1}\)…
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