Identify the type of reaction and also mention the reason for the colour changes observed along with balanced equation, when: a) silver chloride is exposed to sunlight. b) hydrated ferrous sulphate is heated. c) when sodium sulphate is added to barium chloride.
Answers
Answer:
a) Decomposition reaction
b) Decomposition reaction
c) Double displacement reaction
Explanation:
a) Sunlight carries a good amount of energy, which makes silver chloride (AgCl) decompose in silver (Ag) and chlorine. The metallic silver appears as very small 'flakes', essentially black, so these tiny black spots evenly distributed in the mass of white silver chloride makes it look grey.
AgCl ---> Ag+Cl
b) The formula is FeSO4⋅7H2O . When we heat these crystals, they turn white water due to the loss of the water molecules and formation of anhydrous ferrous sulphate which is FeSO4 thus we obtain a white coloured anhydrous compound.
2FeSO4⋅7H2O. →2FeSO4(s)+7H2O(g)
On further heating it decomposes
2FeSO4(s)→Fe2O3(s)+SO3(g)+SO2(g)
Finally the solution turns red brown due to presence of fe2o3.
c) Na2SO4 + BaCl2 --> 2 NaCl + BaSO4
The resulting mixture will be a white ppt. of BaSO4 and colourless solution of NaCl. So, a colourless mixture turns white after this reaction.