Question

5.Give your observations : Observations1. A metal that floats on cold water to form H2 gas. -----------------
2.A metal that sinks in cold H2O to form H2 gas . -----------------
3.The electrode to be electroplated . …………………
4.When H2 gas is passed through vegetable oil it ---------------------
5.When lead reacts with dil H2SO4 a coating forms and reaction --------------- 6.H2+ Cl2 in direct sunlight --------------------- 7.Water formed in lab.is added to anhydrous CuSO4 , colour changes to ---------------
8.When CaCO3 is heated gas evolved ---------------​

Answer 1

Answer:

(i) Iron metal does not react with cold as well as hot water but reacts with steam.

(ii) Metals such as lead, copper, silver and gold do not react with water at all

(b) More heat is evolved during the reaction of sodium metal with water due to which the hydrogen gas formed catches fire. On the other hand, less heat is evolved during the reaction of calcium metal with water which cannot make hydrogen gas burn.