Question

4. Give reasons for the following:
(1) Hydrogen is not collected by downward displacement of air even though it is lighter than air.
(in) Hydrogen is evolved when dilute HCl reacts with zinc but no reaction takes place with copper.
(it) Pure zinc is not used in the laboratory preparation of hydrogen.
(iv) Sodium is not used for the preparation of hydrogen from dilute hydrochloric acid or dilute
sulphuric acid.
(v) Though lead is above hydrogen in activity series, it is not used for the preparation of hydrogen
by treatment with dilute sulphuric acid.​

Answer 1

Answer:

New Delhi: The Chipko movement was a turning point in the forest conservation efforts in India. During the 1970s, when reckless cutting of trees started affecting people's livelihoods, the villagers from Uttarakhand's Chamoli started hugging trees to prevent them from cutting. This movement, where women participated in large numbers, came to be known as Chipko andolan, with the word "Chipko" signifying a hug or embrace. The champions of the Chipko movement were local women - Gaura Devi, Sudesha Devi and Bachni Devi.