Page 164 - ICSE Chemistry 8

5. Which of the following metals reacts violently with hydrogen?
(a) Calcium (b) Magnesium
(c) Iron (d) Sodium

6. Calcium liberates hydrogen when treated with _____________.
(a) cold water (b) hot water (c) steam (d) all of these

7. The conduc vity of water can be increased by adding
(a) a few drops of dilute sulphuric acid. (b) a few pellets of zinc.
(c) both (a) and (b). (d) none of these.
8. The catalyst(s) used in the hydrogena on of oils is/are __________.

(a) nickel (b) pla num (c) palladium (d) all of these
9. Which of the following is a hydrogen-based fuel?

(a) CNG (b) Petroleum (c) Coal (d) Coal gas
10. Reduc on reac on involve(s) ______________.
(a) addi on of oxygen (b) addi on of hydrogen
(c) removal of oxygen (d) both (b) and (c)

SHORT AND PRECISE

A. Show the given text in the form of fl owcharts.
1. Bosch process
2. Physical and chemical proper es of hydrogen

B. Answer in short.
1. Metals like copper and silver cannot displace hydrogen from acids or water.

2. Dilute nitric acid is not used to prepare hydrogen.

3. The fi rst few bubbles of hydrogen gas are not collected during the laboratory prepara on of
hydrogen.

C. Answer in short.
1. What is a displacement reac on?

2. What happens when dilute sulphuric acid and dilute hydrochloric acid are treated with metals
placed above hydrogen in the ac vity series of metals?
3. How can hydrogen be prepared by the ac on of alkalis on metals?

4. How is water gas produced in Bosch’s process?
5. With the help of an ac vity, show that hydrogen gas is combus ble.

6. What happens when hydrogen reacts with carbon?
7. How will you test the presence of hydrogen?

8. What is cataly c hydrogena on of oils?

150