NCERT Solutions for Class 10 Science Chapter 1 - Acids Bases And Salts

Question 1:

What is the common name of the compound ${\mathrm{CaOCl}}_2$

Question 2:

Name the substance which on treatment with chlorine yields bleaching powder.

Question 3:

Name the sodium compound which is used for softening hard water.

Question 4:

What will happen if a solution of sodium hydrogen carbonate is heated? Give the equation of the reaction involved.

Question 5:

Write an equation to show the reaction between Plaster of Paris and water.

Question 6:

10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be:

1. 4 mL
2. 8 mL
3. 12 mL
4. 16 mL

Question 7:

Why does not distilled water conduct electricity, whereas rainwater does?

Question 8:

Plaster of Paris should be stored in a moisture-proof container. Explain why?

Question 9:

What is a neutralisation reaction? Give two examples.

Question 10:

Give two important uses of washing soda and baking soda.

Question 11:

Match the important chemicals given in Column (A) with the chemical formulae given in Column (B).

Question 12:

How would you distinguish between baking powder and washing soda by heating?

Question 13:

Salt ‘A’ commonly used in bakery products on heating gets converted into another salt ‘B’ which itself is used for removal of hardness of water and a gas ‘C’ is evolved. The gas ‘C’ when passed through lime water, turns it milky. Identify ‘A’, ‘B’ and ‘C’.

Question 14:

In one of the industrial processes used for manufacturing sodium hydroxide, a gas ‘X’ is formed as a by-product. The gas ‘X’ reacts with lime water to give a compound ‘Y’ which is used as a bleaching agent in chemical industry. Identify ‘X’ and ‘Y’ giving the chemical equation of the reactions involved.

Question 15:

Fill in the missing data in the following table

Question 16:

For making cake, baking powder is taken. If at home your mother uses baking soda instead of baking powder in cake,

1. How will it affect the taste of the cake and why?
2. How can baking soda be converted into baking powder?
3. What is the role of tartaric acid added to baking soda?

Question 17:

A metal carbonate ‘X’ on reacting with an acid gives a gas which when passed through a solution ‘Y’ gives the carbonate back. On the other hand, a gas ‘G’ that is obtained at anode during electrolysis of brine is passed on dry ‘Y’. It gives a compound ‘Z’, used for disinfecting drinking water. Identity ‘X’, ‘Y’, ‘G’ and ‘Z’.

Question 18:

A sulphate salt of Group 2 element of the Periodic Table is a white, soft substance, which can be moulded into different shapes by making its dough. When this compound is left in the open for some time, it becomes a solid mass and cannot be used for moulding purposes. Identify the sulphate salt and why does it show such a behaviour? Give the reaction involved.

Question 19:

Zinc liberates hydrogen gas when reacted with dilute hydrochloric acid, whereas copper does not. Explain why?

Question 20:

You have two solutions, A and B. The pH of solution A is 6 and the pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic?

Question 21:

What effect does the concentration of ions have on the nature of the solution?

Question 22:

Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?

Question 23:

A solution turns red litmus blue, its pH is likely to be:

1. 1
2. 4
3. 5
4. 10

Question 24:

Five solutions A, B, C, D and E when tested with universal indicator showed the pH as 4, 1, 11, 7 and 9 respectively. Which solution is

1. neutral?
2. strongly alkaline?
3. strongly acidic?
4. weakly acidic?
5. weakly alkaline?

Arrange the pH in increasing order of hydrogen-ion concentration.

Question 25:

Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.

Question 26:

A milkman adds a very small amount of baking soda to fresh milk.

1. Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
2. Why does this milk take a long time to set as curd?

Question 27:

A student prepared solutions of (i) an acid and (ii) a base in two separate beakers. She forgot to label the solutions and litmus paper was not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?