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Enthalpy of Neutralisation

2.480 g of ...

Question

2.480 g of $K C l O_{3}$ are dissolved in conc. HCl and the solution was boiled. Chlorine gas evolved in the reactions was in then passed through a solution of KI and liberated iodine was titrated with 100 ml of hypo. 12.3 ml of same hypo solution required 24.6 ml of 0.5 iodine for complete neutralization. Calculate % purity of $K C l O_{3}$ sample.

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Solution

From the given data we can write the following equation.
$2 K C l O_{3} + 12 H C l ⟶ 2 K C l + 6 H_{2} O + 6 C l_{2}$
$C l_{2} + 2 K I ⟶ 2 K C l + I_{2}$
Molar equivalent of $I_{2}$ = Molar equivalent of Hypo= $100 \times 1$
$m M$ of $C l_{2} = m M$ of $I_{2} = \frac{100}{2} = 50$
$m M$ of $K C l O_{3} = \frac{2 \times m M of C l_{2}}{6} = \frac{2 \times 50}{6} = \frac{50}{3}$
$∴ \frac{W}{122.5} \times 1000 = \frac{50}{3}$
$∴ K C l O_{3} = 2.042$
$∴$ % of $K C l O_{3} = \frac{2.042}{2.48} \times 100 = 82.32$ %

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K C l O_{3}

are dissolved in cone. HCl and the solution was boiled. Chlorine gas evolved in the reaction was then passed through a solution of KI and liberated iodine was titrated with 100 mL of hypo. 12.3 mL of same hypo solution required 24.6 mL of 0.5 N iodine for complete neutralization. Calculate % purity of

K C l O_{3}

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g of a sample of bleaching powder was dissolved in

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8.7

g of pyrolusite (impure

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Q. 5 g of pyrolusite (impure

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2.5

g sample of copper is dissolved in excess of

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10

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Percentage of purity of sample is:

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