Question

State your observations in each of the following reactions:

[ No equation is required, no names of reactants and products are expected in this question]

(i) Iodine crystals are heated in a test tube.

(ii) Copper spoon is kept in silver nitrate solution.

(iii) Lead nitrate crystals are heated.

(iv) Ferric chloride is kept exposed to the atmosphere.

(v) A bottle containing washing soda is kept exposed.

​

Answer 1

1. Answer:

Explanation:

1. Iodine crystals are heated in a test tube? (ii) Iron nails are added to copper sulphate solution? (i) When Iodine crystals are heated, the van der Waals forces are easily overcome and the molecule breaks into the gas phase. They sublime and form a purple colored dense vapor.
2. Copper metal is more reactive than silver metal thus, when copper spoon is kept immersed in silver nitrate solution for some time, it displaces silver from silver nitrate solution. The grey solid crystal of Ag metal are seen growing on the copper spoon and solution turns blue in colour.
3. When lead nitrate crystals are heated strongly, a reddish brown coloured gas is released. This is nitrogen dioxide gas. It has an irritating odour. It turns moist blue litmus red.
4. When ferric chloride is exposed to atmosphere FeCl3 absorbs moisture from the atmosphere and gets converted into its solution. Answer: This compound gets hydrated. ... When this is kept away room the atmosphere, it is anhydrous in nature which means this compound lacks water of crystallization.
5. When sodium carbonate crystals are exposed to air They lose water of crystallization and turn to white powder. This process of loosing water of crystallization when exposed to air is called efflorescence.