How is the concentration of hydronium ions H₃O⁺ affected when a solution of an acid is diluted?

2

(a)

How is the concentration of hydroxide ions (OH^-) affected when excess base is dissolved in a solution of sodium hydroxide?

2

(a)

Write an equation to show the reaction between plaster of paris and water.

2

(a)

Write word equations and then balanced equations for the reaction taking place when
(a) dilute sulphuric acid reacts with zinc granules.
(b) dilute hydrochloric acid reacts with magnesium ribbon
(c) dilute sulphuric acid reacts with aluminium powder
(d) dilute hydrochloric acid reacts with iron filings.

2

(a)

A milkman adds a very small amount of baking soda to fresh milk.
(i) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(ii) Why does this milk take a long time to set as curd?

2

(a)

What happens when nitric acid is added to egg shell?

2

(a)

Write the chemical formula for washing soda.  How may it be obtained from baking soda? Name an industrial use of washing soda other than washing clothes.

2

(a)

What is 'Baking Powder'? How does it make the cake soft and spongy?

2

(a)

What is the colour of litmus in a solution of ammonium hydroxide?

2

(a)

Two solutions A and B have pH values of 5 and 8 respectively.  Which solution will be basic in nature?

2

(a)

Explain why, an aqueous solution of sodium sulphate is neutral while an aqueous solution of sodium carbonate is basic in nature.

2

(a)

HCl and HNO₃ show acidic characteristics in aqueous solution while alcohol and glucose solutions do not. Give reasons.

2

(a)

The colour of copper sulphate solution changes when an iron nail is dipped in it. State the reason giving chemical equation for the reaction involved.

2

(a)

(i) What would be the colour of the solution when copper oxide and dilute hydrochloric acid are mixed?
(ii) Write a chemical equation which represents that the effect of a base is nullified by an acid and vice-versa.

2

(a)

While constructing a house, a builder selects marble flooring and marble table tops for the kitchen where vinegar and juice of lemon, tamarind etc. are more often used for cooking. Will you agree to this selection and why?

2

(a)