Page 29 - Chemistry - XI

After 50% neutralisation, pH of solution is _________ and solution is _________.

After 75% neutralisation, pH of solution is _________ and solution is _________.
After complete neutralisation, pH of solution is _________ and solution is _________.

VIVA VOCE

Q1. What is pH of 0.1 M HCl?
Ans. pH = 1

Q2. What is pH of 0.1 M NaOH?
Ans. pH = 13

Q3. What is pH of 0.1 M NaCl solution?
Ans. pH = 7
Q4. Is pH = 13, strong base or weak base?
Ans. Strong base

Q5. Will pH of 0.1 M acetic acid be same as that of 0.1 M HCl?
Ans. No, acetic acid is a weak acid, HCl is a strong acid.

Q6. If two acidic solutions are mixed, what will happen to the pH of mixture?
Ans. pH of mixture will be in between pH of both the acids.
Q7. 0.1 M HCl and 0.05 M H SO have same pH, why?
4
2
Ans. It is [H O ] = 0.1 M in both the cases as H SO is a dibasic acid.
+
4
2
3
Q8. What happens to pH on dilution of acid and base?
Ans. pH of acids increases, base decreases.
Q9. How do you explain the results of variation of pH with dilution?
Ans. On dilution, H O conc. decreases. pH increases in case of acids. In bases, OH decreases,
–
+
3
H O increases, hence pH decrease.
+
3
COMPETENCY BASED QUESTIONS

Multiple Choice Questions

Q1. Which of the following when added increases the pH of CH COOH?
3
(a) CH COONa (b) HCl (c) NaCl (d) H SO
3 2 4
Q2. Which of the following can replace CH COONa in CH COOH + CH COONa?
3
3
3
(a) CH COOK (b) CH COONH (c) HCl (d) NH 3
4
3
3
Q3. Suggest pairs of weak acid and its salt, among the following
(a) H CO + Na CO (b) NH OH + NH NO
2 3 2 3 4 4 3
(c) NH OH + NH Cl (d) NaCl + Na CO
4 4 2 3
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