Which one of these has a higher concentration of H⁺ ions? 1 M HCl or 1 M CH₃COOH.

Why does 1 M HCl solution have a higher concentration of H⁺ ions than 1 M CH₃COOH solution?

What is common name of the compound CaOCl₂?

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

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

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

A student dropped few pieces of marble in dilute HCl contained in a test tube. The evolved gas was passed through lime water.

(a) What change would be observed in lime water?

(b) Write balanced chemical equation for the above change.

What is the colour of FeSO₄.7H₂O crystals? How does this colour change upon heating? Give balanced chemical equation for the changes.

Name the acid present in the following:

(a) Tomato

(b) Vinegar

(c) Tamarind

(a) What is an alkali? Give an example.

(b) Why do HCl, HNO₃, etc. show acidic characters in aqueous solutions while solutions while solutions of compounds like alcohol and glucose do not show acidic character?

Fill in the missing data in the following table:

A white coloured powder is used by doctors for supporting fractured bones.

(a) Write chemical name and formula of the powder.

(b) When this white powder is mixed with water a hard-solid mass is obtained. Write balanced chemical equation for the change.

A gas ‘X’ reacts with lime water and forms a compound ‘Y’ which is used as a bleaching agent in chemical industry. Identify ‘X’ and ‘Y’. Give the chemical equation of the reactions involved.

A compound which is prepared from gypsum has the property of hardening when mixed with proper quantity of water.

(a) Identify the compound.

(b) Write the chemical equation for its preparation.

(c) Mention one important use of this compound.

Explain the following chemical properties of acids with the help of balanced chemical equations only.

(i) when an acid reacts with a metal carbonate

(ii) when an acid reacts with a metal bicarbonate

(iii) when an acid reacts with a metal oxide

You are given three solutions A, B and C with pH values 2, 10 and 13 respectively. Write which solution has more hydrogen ions concentration among the three and state the nature ‘acidic or basic’ of each solution.

A metal compound ‘X’ reacts with dil.H₂SO₄ to produce effervescence. The gas evolved extinguishes a burning candle. If one of the compounds formed is calcium sulphate, then what is ‘X’ and the gas evolved? Also, write a balanced chemical equation for the reaction which occurred.

(i) Name one antacid. How does it help to relieve indigestion in stomach?

(ii) A farmer treats the soil with quicklime or calcium carbonate. What is the nature of soil? Why does the farmer treat the soil with quicklime?

In the following schematic diagram for the preparation of hydrogen gas as shown in the given figure, what would happen if the following changes are made?

(a) In place of zinc granules, same amount of zinc dust is taken in the test tube.

(b) Instead of dilute sulphuric acid, dilute hydrochloric acid is taken.

(c) In place of zinc, copper turnings are taken.

(d) Sodium hydroxide is taken in place of dilute sulphuric acid and the tube is heated.

(a) Identify the acid and the base whose combination forms the common salt that you use in your food. Write its formula and chemical name of this slat. Name the source from where it is obtained.

(b) What is rock salt? Mention its colour and the reason due to which it has this colour.

(c) What happens when electricity is passed through brine? Write the chemical equation for it.

(a) Identify the compound of calcium which is yellowish white powder and is used for disinfecting drinking water. Write its chemical name and formula. How is it manufactured? Write the chemical equation for the reaction involved. Also list two other uses of the compound.

(b) Write the balanced chemical equation of chlor-alkali process.

(a) Crystals of a substance changed their colour on heating in a closed test tube but regained it after sometime when they were allowed to cool down. Name the substance and write its formula and explain the phenomenon involved.

(b) Name the compound whose one formula unit is associated with 10 water molecules. How is it prepared? Give equations of related reactions. Give two uses of the compound.

Hritik tested rainwater and found a pH of 5-6 due to presence of H⁺ ions formed by reaction of rainwater with carbon dioxide. When pH of the rainwater drops below 5-6, then it is called acid rain. Oxides of nitrogen and sulphur are acidic in nature. Burning of fossil fuels such as coal and oil in power stations and furnace produce oxides of nitrogen and sulphur. He told all of his classmates living nearby to use bicycle instead of school bus so as to reduce air pollution and prevent acid rain.

(a) Which acid is formed by sulphur dioxide in presence of air?

(b) Which acid is formed by nitrogen dioxide in presence of air?

(c) Why is acid rain harmful for agriculture, trees and plants?

(d) How can we prevent from acid rain?

(e) What values are possessed by Hiritik?