Page 173 - Chemistry ICSE Class IX

Study of the First Element : Hydrogen 161
Complete and balance the following chemical equations:
(a) Zn(s) + H O(g) o _________________
2
(b) K(s) + H O(l) o _________________
2
steam
(c) Zn(s) + NaOH(aq) o _________________
(hot, conc.)
(d) Fe O (s) + H (g) o _________________
2
3
2
hot
(e) C H (g) + H (g) o _________________
4
2
2
(f) N (g) + H (g) o _________________
2
2
Name a black (a) oxidising agent (b) reducing agent
Name the products formed when steam is reacted with water gas at 800°C in the presence of a catalyst. (a) Name
the catalyst (b) Write the balanced chemical equation.
Why are nitric acid and conc. sulphuric acid not used in the preparation of hydrogen?
How can you justify that hydrogen is very useful for industry?
Tick (9) the correct answer.
(i) Hydrogen was rst prepared by
(a) Henry Cavendish ˆ
(b) Paracelsus ˆ
(c) Antoine Lavoisier ˆ
(d) Robert Boyle ˆ
(ii) Which of the following metals is used for preparing hydrogen?
(a) nickel ˆ
(b) molybdenum ˆ
(c) copper ˆ
(d) iron ˆ
(iii) In the reaction involving water, an active metal produces
(a) oxygen ˆ
(b) nitric acid ˆ
(c) a base ˆ
(d) nitrogen ˆ
(iv) In the preparation of vanaspati ghee, the chemical reaction involving hydrogen in the presence of catalyst is
called
(a) reduction ˆ
(b) dehydrogenation ˆ
(c) hydrogenation ˆ
(d) oxidation ˆ
(v) Hydrogen does not reduce heated
(a) Al O ˆ
2
3
(b) CuO ˆ
(c) SnO ˆ
2
(d) Fe O ˆ
3
4
Answers

(i) (b) (ii) (d) (iii) (c) (iv) (c) (v) (a)