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Standard XII

Chemistry

Decarboxylation

When 400 ml o...

Question

When 400 ml of 0.2 M acetic acid is mixed with 800 ml of 0.5 M solution, NaOH of heat is liberated. The amount of heat utilised for complete dissociation of 4.416 KJ acetic acid is $(0.3 \times y) K J / m o l$ . The value of ‘y’ is ___

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Solution

No of moles of solute $= m o l a r i t y \times v o l u m e o f s o l u t i o n$
No. of moles of acid $= 0.2 \times 400 m l = 80 m m o l$
No. of moles of base $= 0.5 \times 800 m l = 400 m m o l$
$C H_{3} C O O H + N a O H ⟶ C H_{3} C O O N a + H_{2} O$
$80 m m o l 400 m m o l 80 m m o l$
(For $C H_{3} C O O H$ and $N a O H$ mole and equivalent are the same because both have value of $n - f a c t o r = 1$ )
No. of equivalents of acid or base neutralised completely = $\frac{80 m i l i e q .}{1000}$
$\frac{80}{1000}$ equivalents give $\to$ 4.416 KJ
$∴$ 1 equivalent give $\to \frac{4.416}{80} \times 1000 = 55.2 k J$
$∴$ heat of ionisation of $C H_{3} C O O H = - 55.2 + 57.3 = + 2.1 k J / m o l e$

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When 400 ml of 0.2 M acetic acid is mixed with 800 ml of 0.5 M solution, NaOH of heat is liberated. The amount of heat utilised for complete dissociation of 4.416 KJ acetic acid is (0.3×y)KJ/mol. The value of ‘y’ is ___

When 400 ml of 0.2 M acetic acid is mixed with 800 ml of 0.5 M solution, NaOH of heat is liberated. The amount of heat utilised for complete dissociation of 4.416 KJ acetic acid is $(0.3 \times y) K J / m o l$ . The value of ‘y’ is ___