InterviewSolution
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InterviewSolution
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Which one of the following will decrease the pH of 50 mL of 0.01 M hydrochloric acid ?A. Addition of 50 mL of 0.01 M HClB. Addition of 50 mL of 0.002 M HClC. Addition of 150 mL of 0.002 M HClD. Addition of 5 mL of 1 M HCl |
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Answer» Correct Answer - D For 0.01 M HCl, `[H^(+)]=10^(-2)M`, pH=2 (a) `N_(1)V_(1)+N_(2)V_(2)=N_(3)(V_(1)+V_(2))` `50xx0.01+50xx0.01=N_(3)(50+50)` or `N_(3)=(0.5+0.5)/(100)=10^(-2), pH=2` (No change) (b) `50xx0.01+50xx0.02=N_(3)(50+50)` or, `N_(3)=(0.5+0.1)/(100)=6xx10^(-3)` `pH=-log(6xx10^(-3))=2.22` (pH increases) (c) `50xx0.01+150xx0.002=N_(3)(50+150)` or, `N_(3)=(0.5+0.3)/(200)=4xx10^(-3)` `pH=-log(4xx10^(-3))=2.39` (pH increases) (d) `50xx0.01+5xx1=N_(3)(50+5)` or, `N_(3)=(0.5+5)/(55)=(55)/(5)=10^(-1)` pH = 1 (pH decreases) |
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