Science : Ch 01 – Chemical Reactions and Equations

Give an example of decomposition reaction taking place in our body.

What happens when sodium sulphate solution is added to barium chloride solution?

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

Identify the reducing agent in the following reactions: 2H₂ + O₂ → 2H₂O

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

Mention whether it is physical or chemical changes : Heating of an iron rod to red hot

State the reactions exothermic or endothermic in nature: Dilution of sulphuric acid

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

In the electrolysis of water, name the gases liberated at anode

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

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

Which of the following reactions is an endothermic reaction?

One of the following does not happen during a chemical reaction.

Dilute hydrochloric acid is added to granulated zinc taken in a test tube. The following observations are recorded. Designate the accurate observation:

Three beakers labelled as A, B and C, each containing 25 ml of water, were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in the case of beaker C, the temperature of the solution fell. Which one of the following statement(s) is (are) correct?

1. In beakers A and B, exothermic process has occurred.
2. In beakers A and B, endothermic process has occurred
3. In beaker C, exothermic process has occurred
4. In beaker C, endothermic process has occurred.