## Assertion and Reason

#### Assertion and Reason

Direction: Choose the correct alternative from the following options as given below for the Assertion (A) and Reason (R) given in each of the questions.

1. Assertion (A)
Alcohol rather than mercury is used in a thermometer to measure a temperature of - 60 C.
Reason (R)
Alcohol has a lower freezing point than mercury.
1. if both A and R are true and R is the correct explanation of A
2. if both A and R are true and R is not the correct explanation of A
3. if A is true but R is false
4. if A is true but R is true

1. We know that, mercury freezes at -39 C, while alcohol freezes at a point far below - 100 C. So, alcohol is used to measure lower temperatures. Similarly, mercury boils at 357 C, while alcohol boils at 78 C. So, mercury is used to measure high temperature.

##### Correct Option: A

We know that, mercury freezes at -39 C, while alcohol freezes at a point far below - 100 C. So, alcohol is used to measure lower temperatures. Similarly, mercury boils at 357 C, while alcohol boils at 78 C. So, mercury is used to measure high temperature.

1. Assertion (A)
Tides indicate the regular and periodic rise and fall in sea level.
Reason (R)
Tides are caused by the gravitational pull of the Moon and sea level.
1. if both A and R are true and R is the correct explanation of A
2. if both A and R are true and R is not the correct explanation of A
3. if A is true but R is false
4. if A is true but R is true

1. Both the assertion and reason are true but reason are true but reason is not the correct explanation of assertion.

##### Correct Option: B

Both the assertion and reason are true but reason are true but reason is not the correct explanation of assertion.

1. Assertion (A)
Graphite is slippery and used as a lubricant.
Reason (R)
Graphite has free electrons.
1. if both A and R are true and R is the correct explanation of A
2. if both A and R are true and R is not the correct explanation of A
3. if A is true but R is false
4. if A is true but R is true

1. In graphite, each carbon atoms is linked to three other carbon atoms, while one electron in the carbon atom is delocalised. So, graphite has free electrons and it is also used as a lubricant but reason does not explains assertion.

##### Correct Option: B

In graphite, each carbon atoms is linked to three other carbon atoms, while one electron in the carbon atom is delocalised. So, graphite has free electrons and it is also used as a lubricant but reason does not explains assertion.

1. Assertion (A)
When common salt is kept open, it absorbs moisture from the air.
Reason (R)
Common salt contains magnesium chloride.
1. if both A and R are true and R is the correct explanation of A
2. if both A and R are true and R is not the correct explanation of A
3. if A is true but R is false
4. if A is true but R is true

1. We know that, common salt contains magnesium chloride. Therefore, it absorbs moisture from the air.

##### Correct Option: A

We know that, common salt contains magnesium chloride. Therefore, it absorbs moisture from the air.

1. Assertion (A)
The steam engine was invented by James Watt.
Reason (R)
There was a problem of taking out water from flooded mines.
1. if both A and R are true and R is the correct explanation of A
2. if both A and R are true and R is not the correct explanation of A
3. if A is true but R is false
4. if A is true but R is true

1. Assertion is correct but reason is false.

##### Correct Option: C

Assertion is correct but reason is false.