A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?

Which of the following are exothermic processes?

1. Reaction of water with quick time

2. Dilution of an acid

3. Evaporation of water

4. Sublimation of camphor (crystals)

Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of Na0H, anhydrous CuSO₂ 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 case of beaker C, the temperature of the solution falls. Which one of the following statement (s) is (are) correct?

1. In beakers A and B, exothermic process has occurred.

2. In breakers A and B, endothermic process has occurred.

3. In breaker C, exothermic process has occurred.

4. In beaker C, endothermic process has occurred.

Which among the following (are) double displacement reaction (s)?

(i) Pb + CuCl₂ PbCl₂+Cu

(ii) Na₂SO₄+BaCl₂BaSO₄+2NaCl

(iii) C+O₂CO₂

(iv) CH₄+2O₂CO₂+2H₂O

Which among the following statement (s) is (are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to

(i) the formation of silver by decomposition of silver chloride.

(ii) sublimation of silver chloride.

(iii) decomposition of chlorine gas from silver chloride.