Science : Ch 01 – Chemical Reactions and Equations

Which reaction takes place when layer of silver deposit on copper wire when dipped in silver nitrate solution?

Why are oil and fat containing food items fushed with nitrogen while packing?

Identify the reducing agent in the following reactions: Fe₂O₃ + 3CO → 2Fe + 3CO₂

When hydrogen sulphide gas is passed through a blue solution of copper sulphate, the colour of the solution fades and a black precipitate is obtained.Write the chemical name of the black precipitate formed.

Mention whether it is physical or chemical changes:- Burning of Liquefied Petroleum Gas (LPG)

Mention whether it is physical or chemical changes: Sublimation of solid ammonium chloride

State the reactions are exothermic or endothermic in nature: Decomposition of ferrous sulphate

Sate the reactions exothermic or endothermic in nature: Dissolution of sodium hydroxide in water

Solid calcium oxide reacts vigorously with water to form calcium hydroxide, accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form a solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?

1. It is an endothermic reaction
2. It is an exothermic reaction.
3. The pH of the resulting solution will be more than seven.
4. The pH of the resulting solution will be less than seven

Which of the subsequent is (are) an endothermic process(es)?

1. Dilution of sulphuric acid
2. Sublimation of dry ice
3. Condensation of water vapours
4. Evaporation of water

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during the electrolysis of water is:

Strong heating of ferrous sulphate leads to the formation of a brown solid and two gases. This reaction can be designated as:

When hydrogen sulphide gas is passed through a blue solution of copper sulphate a black precipitate of copper sulphide is obtained and the sulphuric acid so formed remain in the solution. The reaction is an example of a:

When copper turning are added to silver nitrate solution, a blue coloured solution is formed after some time. It is because copper ?

The following reaction is used for the preparation of oxygen gas in the laboratory: 2KClO₃(s) Heat ⎯ → Catalyst ⎯⎯⎯ 2KCl(s) + 3O₂(g) Which of the following statement(s) is/are correct about the reaction?