pH of Acids and Bases

Q.

Is coffee a base or acid?

Q.

What effect does an increase in concentration of $H^{+}$ (aq) in a solution have on the pH of solution ?

Q.

Calculate the pH of the solution if the hydrogen ion concentration of the solution is 0.0001M.

1. Blue-green colour
2. Purple colour
3. Orange colour
4. Red colour

Q. What is a buffer solution?

Q. Pure water is neutral and, hence, it has a pH of 0.

1. True
2. False

Q.

When pH decreases, the hydrogen ion concentration increases.

1. True

2. False

Q.

How does the pH change when the solution of base is diluted with water? [2 MARKS]

Q.

What is the importance of pH?

1. It measures the strength of acids only.

2. It measures the strength of bases only.

3. It measures the concentration of hydroxide ions only.

4. It measures the strength of both acids and bases.

Q.

pH is a measure of the concentration of protons in a solution.

1. True

2. False

Q. What is the pH value of pure water?

Q. Sort the following according to the colours shown by the universal indicator in the increasing order of pH value.

1. Red
2. Purple
3. Dark Blue
4. Green
5. Yellow

Q.

Q. Question 9(e)
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is
(e) weakly alkaline?

Q.

Choose the correct option.

pH of basic solution is _____________.

1. Less than 7

2. Equal to 7

3. More than 7

4. None of these

Q. The variation of pH during the titration of 0.5 N $N{a}_{2}C{O}_3$ with 0.5 N HCI is shown in the given graph, the following table indicates the colour and pH ranges of different indicators :

Indicator	Range of colour change	colour in acid	colour in base
Thymol blue	1.2 to 2.8	Red	Yellow
Bromocresol red	4.2 to 6.3	Red	Yellow
Bromothymol blue	6.0 to 7.6	Yellow	Blue
Cresolphethalain	8.2 to 9.8	Colourless	Red

Based on the graph and the table, which of the following statements are true?

1. The first equivalence point can be detected by cresolphthalein
2. The complete neutralisation can be detected by bromothymol blue
3. The second equivalence point can be detected by bromocresol red
4. The volume of HCI required for the first equivalence point is half the volume of HCI required for the second equivalence point

Q. What is pH?

1. $log\left[H^{+}\right]$
2. $-log[OH{]}^{-}$
3. $-log\left[H^{-}\right]$
4. $-log\left[H^{+}\right]$

Q. Question 9(b)
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is
(b) strongly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.

Q. If the concentration of hydronium ions in a solution is ${10}^{-4}\text{M}$, then the pH of this solution is:

1. 4

Q. Solve the following problems :
How many times concentrated will be the aqueous solution having pH $11.9$ as compared to aqueous solution having pH $8$ ?

Q. The term pH is defined as:

1. log 1/($H^{+}$)
2. -log 1/($H^{+}$)
3. log $H^{+}$
4. -log $(H^{+}{)}^2$

Q. From the given options select the one with the highest pH value.

1. $\text{HCl}$
2. ${\text{H}}_2{\text{SO}}_4$
3. ${\text{H}}_2\text{O}$
4. $\text{NaOH}$

Q. pH scale is used for measuring _____ ion concentration in a solution.

1. oxygen
2. nitrogen
3. hydrogen
4. chlorine

Q. If ion concentration increases then the pH .

1. $H_3{O}^{+}$
2. decreases
3. remains same
4. $O{H}^{-}$

Q. The range of pH scale is from:

1. 1 to 10
2. 0 to 7
3. 2 to 17
4. 0 to 14

Q. The solution with pH = ___ has highest hydronium ion concentration.

1. 1
2. 7
3. 14
4. 5.5

Q. The pH of two solutions A and B are 11 and 7.7 respectively. What can you say about the nature of these solutions?

1. A is strongly acidic and B is weakly acidic.
2. A is strongly basic and B is weakly basic.
3. Both A and B are strongly acidic.
4. Both A and B are strongly basic.

Q.

A solution has a pH value of 2. It can be concluded that the given solution is _______ in nature.

1. strongly basic

2. weakly basic

3. strongly acidic

4. weakly acidic

Q. If the pH value of a solution is 7, then the solution is said to be _______.

1. acidic
2. neutral
3. slightly basic
4. highly basic

Q. Which is more basic (or more alkaline): a solution of pH = 8 or a solution of pH = 11?