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40 ml of `0.1` M ammonia is mixed with 20 ml of `0.1 M HCI`. What is the pH of the mixture ? (`pK_(b)` of ammonia solution is `4.74.`)A. 4.74B. 2.26C. 9.26D. `5.00` |
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Answer» Correct Answer - C 40 Ml of 0.1 M HCl `=20 xx 0.1` milli mole `=2` milli mole `NH_(4)OH+HCl rarr NH_(4)Cl +H_(2)O` 2 milli mole of HCl will neutralize 2 milli moles of `NH_(4)OH` to form 2 milli moles of `NH_(4)Cl`. `NH_(4)OH ` left `=2 ` milli moles Total volume `=60 mL` `:. [NH_(4)OH]=2//60M,[NH_(4)Cl]=2//60M` ` pOH =pK_(b)+log.([NH_(4)Cl])/([NH_(4)OH])` `=4.74 +log. (2//60)/(2//60)=4.74` `:. pH =14-4.74 =9.26` |
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