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Standard XII

Chemistry

Salt of Strong Acid and Strong Bases

How many g mo...

Question

How many g moles of HCl will be required to prepare one litre of buffer solution (containing NaCN and HCN) of pH= 8.5 using 0.01 gm formula mass of NaCN. $K_{a} (H C N) = 4.1 \times 10^{- 10}$

0.0089 mole

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0.0081 mole

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0.0082 mole

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0.0080 mole

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Solution

The correct option is A 0.0089 mole
$N a C N + H C l \to N a C l + H C N$
$[N a C N] = (0.01 - a), [H C N] = a$
$∴ p^{H} = p K_{a} + l o g \frac{[N α C N]}{[H C N]}$
$8.5 = l o g \frac{0.01 - α}{α} l o g 4.1 \times 10^{- 10}$
$∴ l o g \frac{0.01 - α}{α} = 8.5 + 0.617 - 10$
$∴ a = 0.0089 m o l e$

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Similar questions

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How many g moles of HCl will be required to prepare one litre of buffer solution (containing NaCN and HCN) of pH= 8.5 using 0.01 gm formula mass of NaCN. Ka(HCN)=4.1×10–10

The correct option is A 0.0089 mole NaCN+HCl→NaCl+HCN [NaCN]=(0.01−a),[HCN]=a ∴pH=pKa+log[NαCN][HCN] 8.5=log0.01−ααlog4.1×10−10 ∴log0.01−αα=8.5+0.617−10 ∴a=0.0089 mole

How many g moles of HCl will be required to prepare one litre of buffer solution (containing NaCN and HCN) of pH= 8.5 using 0.01 gm formula mass of NaCN. $K_{a} (H C N) = 4.1 \times 10^{- 10}$