Chemistry
(a) Where does Hydrogen occur in free state?
(b) How did the name 'hydrogen' originate?
Answer
(a) In free state, hydrogen is found in traces in earth's crust and atmosphere. Volcanic gases contain 0.025% of it, the earth's crust 0.98%, the earth's atmosphere 0.01% and the atmospheres of the Sun and the stars also contain hydrogen in large amounts.
(b) It is on account of its ability to form water that Lavoisier, in 1783, named it hydrogen (Greek word meaning water former).
Related Questions
Thin strips of magnesium, copper and iron are taken.
(a) Write down what happens when these metals are treated as follows
(i) Heated in presence of air
(ii) Heated with dil. HCl
(iii) Added to an aqueous solution of zinc sulphate
(b) Arrange these metals in descending order of reactivity.
Give the reason for the following
(a) Zinc granules are used in the lab preparation of hydrogen.
(b) Purified and dried hydrogen is collected over mercury.
(c) The end of the thistle funnel should be dipped under acid.
(d) Dilute sulphuric acid cannot be replaced by concentrated acid in the preparation of hydrogen.
Hydrogen can be prepared with the help of cold water. Give a reaction of hydrogen with:
(a) a monovalent metal
(b) divalent metal
Which metal is preferred for preparing hydrogen from:
(a) cold water?
(b) hot water?
(c) steam?
Write balanced equation for each case.