Equilibrium Question 894

Question: In which case change in pH is maximum-

Options:

A) 1 mL of pH = 2 is diluted to 100 mL

B) 0.01 mol of NaOH is added to 100 mL of 0.01 M NaOH solution

C) 100 mL of H2O is added to 900 mL of 106 M HCl

D) 100 mL of pH = 2 solution is mixed with 100 mL of pH = 12

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Answer:

Correct Answer: D

Solution:

pH before pH after Changes [a] 2 4 2 [b] 12 13.04 1.04 [c] 6 6.7 0.7 [d] 2 7 5 Explanation: [a] pH=2.[H+]=102M

M1V1=M2V2

102×1=M2×100

M2=104

pH=4

[b] [OH]=102

pOH=2

pH=12 100 of 0.01 M NaOH

contains 0.001 mol NaOH added - 0.01 mol Total moles = 0.011 mol

[OH1]final=0.011×10=0.11M

pOH=0.96

pH = 13.04 [c] [HCl]=106M

[H+]=106M;pH=6

After dilution [HCl]=107M=[H+]

[H+]in,H2O=107M

Total [H+]=107+107=2×107

pH=7log2=6.7

[d] ,pH=2,,[H+]=102M

pH=12,,[H+]=1012M

,[OH]=102M



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