Physical Test

Q.

Why ${\mathrm{KMnO}}_4$ is a self-indicator?

Q.

Why is the Universal indicator not used in titration?

Q.

Is Tea acidic or basic?

Q. Which of the following is incorrectly matched?

	Indicator	Colour change in basic medium
(1)	Litmus paper	Red to blue
(2)	Methyl orange	Orange to red
(3)	Phenolphthalein	Colourless to pink
(4)	Turmeric	Yellow to reddish brown

1. 1
2. 2
3. 3
4. 4

Q.

Which of the following will turn blue litmus solution red.

1. Lime water

2. Vinegar

3. Baking Soda solution

4. Washing Soda solution

Q. Mention the colour changes observed when the following indicators are added to acids:
(a) Alkaline phenolphthalein solution.
(b) Methyl orange solution.
(c) Neutral litmus solution.

Q.

Chlorine gas is bubbled into the water and subsequently, some blue litmus solution is poured into the water. Predict the observations that would follow.

Q.

The two colors seen at the two extreme ends of the pH chart are:

1. red and violet

2. red and green

3. green and blue

4. orange and green

Q. A solution has a pH of 7. Explain, how you would:
(i) increase its pH
(ii) decrease its pH
If a solution changes the colour of litmus from red to blue, what can you say about its pH?

Q.

Match the following:
$\begin{array}{cc}\text{a) Litmus}& \text{1) Blue in acidic, pink in basic soils}\\ \text{b) Methyl orange}& \text{2) Red in acidic, yellow in basic solutions}\\ \text{c) Phenolphthalein}& \text{3) Blue in basic, red in acidic solutions}\\ \text{d) Color of Hydrangea}& \text{4) Pink in basic, colorless in acidic solutions}\end{array}$

1. A-2, B-3, C-4, D-1

2. A-3, B-2, C-4, D-1

3. A-3, B-4, C-2, D-1

4. A-3, B-1, C-2, D-4

Q.

Why is commercial hydrochloric acid often yellow in colour?

Q.

Which gas turns moist red litmus blue.

Q.

A drop of colourless liquid is poured over blue litmus paper and it turns to red. The colourless liquid is:

1. dilute hydrochloric acid

2. potassium hydroxide solution

3. sodium chloride solution

4. pure water

Q.

Olfactory indicators can be used by visually impaired students.

1. True
2. False

Q. The colour of phenolpthathein indicator in slaked lime is and in nitric acid is .

1. pink
2. orange
3. yellow
4. colourless

Q. ______ is a substance of which smell varies depending on whether it is mixed with an acidic or a basic solution.

1. Gustatory indicator
2. Olfactory indicator
3. Natural indicator
4. Synthetic indicator

Q.

The indicator used to find the pH of a given solution is known as universal indicator because:

1. it is universally available

2. it has a universal appearance

3. it can be used for the entire pH range

4. None of these

Q. The colour of methyl orange indicator in an acid solution is ................... .

Q.

What is the action of litmus on dry ammonia gas and solution of ammonia gas in water?

Q. What is the nature of the substances that do not change the colour of the methyl orange indicator?

1. Neutral
2. Acidic
3. Basic
4. None of the above

Q. Match the following:
$$\begin{array}{cc}a)Litmus& 1)Blueinacidic,pinkinbasicsoils\\ b)Methylorange& 2)Redinacidic,yellowinbasicsolutions\\ c)Phenolphthalein& 3)Blueinbasic,redinacidicsolutions\\ d)ColorofHydrangea& 4)Pinkinbasic,colorlessinacidicsolutions\end{array}$$

1. A-3, B-4, C-2, D-1
2. A-3, B-2, C-4, D-1
3. A-3, B-1, C-2, D-4
4. A-2, B-3, C-4, D-1

Q. A metal contains metal oxide as impurity. The method used to refine this metal is:

1. poling
2. liquation
3. cupellation
4. distillation

Q. The tastes of vinegar and soap respectively are:

1. bitter and sour
2. sour and bitter
3. salty and bitter
4. sour and sweet

Q. Which of the following are not the properties of bases?

1. Bases are sweet in taste.
2. Bases change blue litmus to red.
3. Bases change red litmus to blue.
4. Bases are soapy in touch.

Q. Methyl orange turns _____ colour in basic solution.

1. blue
2. yellow
3. pink
4. red

Q.

What are pH indicators?

1. Aqueous solution of either salts of strong acids or strong bases.

2. Aqueous solution either salts of weak acids or weak bases.

3. Aqueous solution of either weak acids or weak bases.

4. Aqueous solution of either strong acids or strong bases.

Q. In basic medium, which of the following colour is obtained when phenolphthalein is added?

1. Colourless
2. Pink
3. Green
4. Yellow

Q. Methyl orange is used as an indicator. It shows colour changes in acid, base and neutral substance. Tabulate your results as follows:

Indicator	Colour Change	Inference
Methyl Orange	No change	.......
	.........	Acid
	Yellow	......

Q. China rose indicator in acidic solution changes its colour to ________________.

1. yellow
2. blue
3. dark pink
4. green

Q. Match the following indicators to the respective colour change in the acidic or basic medium:

1. Red (acidic)
2. Yellow (basic)
3. Colourless (acidic)
4. Green (basic)