The flocculation value of AlCl3 for an As2S3 sol is 0.093 mmol per litre of sol. What mass of anhydrous AlCl3 (Al = 27, Cl = 35.5) in mg is needed to coagulate 2.5 L of the sol? Ignore any volume change (two decimals).

JEE Advanced levelNumerical answerDifficulty 3 of 3sc202

The flocculation value of $AlCl X_{3}$ for an $As X_{2} S X_{3}$ sol is 0.093 mmol per litre of sol. What mass of anhydrous $AlCl X_{3}$ (Al = 27, Cl = 35.5) in mg is needed to coagulate 2.5 L of the sol? Ignore any volume change (two decimals).

Numerical answer type, answer in mg, tolerance 0.02.

Molar mass of

AlCl X_{3}

= 27 + 3 \times 35.5 = 133.5

g/mol. Moles needed

= 0.093 \times 2.5 = 0.2325

mmol. Mass

= 0.2325 \times 133.5 = 31.04

mg.