Effect on Indicators by Acids,Bases

Q. How is litmus paper prepared?

Q.

Vanilla, clove and onion are ___ indicators.

Q.

Dry $HCl$ gas changes the colour of the litmus paper.

1. True

2. False

Q.

What are indicators used for? Give some examples of naturally occurring indicators. [3 MARKS]

Q. Which of the following is an acid-base indicator?

1. Vinegar
2. Limewater
3. Turmeric
4. Baking Soda

Q. Identify the beaker that contains a mixture of vinegar and china rose indicator.

1. 
2. 
3. 
4. 

Q.

Vanilla, clove and onion are __ indicators.

Q.

What happens when moist blue and red litmus papers are lowered into a jar containing pure oxygen? What does it show?

Q. A teacher gave two test tubes, one containing water and the other containing sodium hydroxide solution, to the students and asked them to identify the test tube containing sodium hydroxide solution. Which one of the following can be used for correctly identifying the test tube containing sodium hydroxide solution?

1. Blue litmus paper
2. Red litmus paper
   
3. Sodium carbonate solution
4. Dilute hydrochloric acid

Q. Oxygen gas is neutral to moist litmus.

1. True
2. False

Q. Which of the following is an acid-base indicator?

1. Vinegar
2. Limewater
3. Turmeric
4. Baking Soda

Q.

When blue litmus paper was dipped into the water, the colour of litmus paper remained the same. Similarly, when red litmus paper was dipped into water, the colour remained the same. By above observation we can concluded that:

1. No conclusion can be made

2. Water is acidic

3. Water is basic

4. Water is neither acidic nor basic

Q.

What is the colour change observed in dil. HCl solution when phenolphthalein is added to it?

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

Q.

Methyl orange is a natural indicator.

1. True

2. False

Q.

Neutral solution changes the color of blue litmus to red.

1. True

2. False

Q. Which of the following is an olfactory indicator?

1. Turmeric
2. Litmus
3. Onion
4. Phenolphthalein

Q. Which of the following is an acid-base indicator?

1. Vinegar
2. Limewater
3. Turmeric
4. Baking Soda

Q. Which of the following is true about anthocyanin pigments in red cabbage and rose petals?

1. They are blue in acidic and red in basic solutions.
2. They are made artificially.
3. They can act as indicators.
4. They can't be used as indicators.

Q.

Identify the properties of a base

1. Slippery, shiny, bitter.

2. Bitter, ablitity to change colors in an indicator, and slippery.

3. Shiny, ablitity to change colors in an indicator, and slippery.

4. Sour, ablitity to change colors in an indicator, shiny.

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.

If a blue litmus paper remains blue after dipping into a solution, then that:

1. Solution is acidic

2. Solution is basic

3. Solution is neither acidic nor basic

4. Solution is either basic or neutral.

Q. In what condition do vanilla, onion and clove lose their smell?

1. Acidic
2. Neutral
3. Basic
4. Never

Q.

Statement 1: In the industrial areas gases like sulphur dioxide and nitrogen dioxide are present in large quantity.
Statement 2: The marble of Taj Mahal is fading away.

1. Both assertion and reason are true and the reason is the correct explanation of assertion
2. Both assertion and reason are true but the reason is not the correct explanation of assertion
3. The assertion is true but the reason is false.
4. Both assertion and reason are false.