Hard Water

Q.

balanced equation of calcium oxide with water

Q.

What is the formula for Hard Water?

Q.

When zeolite is treated with hard water, the sodium ions are exchanged with:

1. ${OH}^{-}$ ions

2. $S{O}_4^{2-}$ions

3. $C{a}^{2+}$ ions

4. $H^{+}$ ions

Q.

Name the salts that cause hardness of water.

Q. Which of the following is the largest source of water?

1. Rivers
2. Oceans
3. Wells
4. Lakes

Q.

Water which forms scum with soap is called

1. soft water

2. hard water

3. distilled water

4. heavy water

Q.

What happens when hard water is treated with washing soda?

Q. in the preparation of iron from haematite by the reaction with carbon Fe2O3 +C ---> Fe + CO2 how much 80% pure iron could be produced from 120kg of 90 % pure Fe2O3 ?

Q. Water is said to be hard when ?

1. It does not lather readily with soap.
2. It does not contain minerals.
3. It contains minerals.
4. It lathers readily with soap.

Q.

The deposit of calcium carbonate in the boiler is a bad conductor of heat.These deposits of calcium carbonate is stone like and is called ___ .

Q. Soft water does not lather with soap easily.

1. True
2. False

Q.

The hardness of water can be detected using ______.

1. electrolysis

2. lathering soap

3. litmus paper

4. thermometer

Q. Is soap a solid ?

Q.

Name the compound (NH₄)₂SO₄

Q. Which of the following is true regarding these statements?

Statement 1: Hard water contains dissolved salts of calcium and magnesium.
Statement 2: Hard water lathers easily with soap.

1. Statement 1 is correct but statement 2 is incorrect
2. Statement 2 is correct but statement 1 is incorrect
3. Both statement 1 and statement 2 are incorrect
4. Both statement 1 and statement 2 are correct

Q. On analysis it was found that FeS contains 36.47% of sulphur . How much FeS will be obtained on heating a mixture of 1.0 g of Fe and 2.0g of S? How much sulphur remains in decomposed?

Q. How to make a soap

Q.

An example of soap is

1. $C_{17}{H}_{35}COONa$
2. $C{H}_{3}COONa$
3. $C{H}_{3}ONa$
4. $C_{17}{H}_{35}COO{C}_2{H}_5$

Q.

List the disadvantage of hard water.

Q. It is advisable to use hard water in industries.

1. True
2. False

Q. Hard water could contain

1. calcium chloride
2. calcium carbonate
3. calcium sulphate
4. calcium bicarbonate

Q.

There are two water samples one in test-tube A and another in test-tube B. It was observed that water in both test-tubes A and B does not give lather with soap. However, after boiling the water in both the test-tubes A and B, the water in test-tube B does give lather with soap. Which among the following statements is correct?

1. Water in both the test-tubes is permanent hard water.

2. Water in test-tube A is permanent hard water while in test-tube B is temporary hard water.

3. Water in test-tube A is temporary hard water while in test-tube B is permanent hard water.

4. Water in both the test-tubes is temporary hard water.

Q. What are the uses of synthetic detergents? [2 Marks]

Q. Slag formed in Blast fumace is:

1. $FeSi{O}_3$
2. $CaSi{O}_3$
3. $CaC{O}_3$
4. Both $\left(1\right)$ & $\left(2\right)$