Question 6
What happens when calcium is treated with water?

(i) It does not react with water.
(ii) It reacts violently with water.
(iii) It reacts less violently with water.
(iv) Bubbles of hydrogen gas formed stick to the surface of calcium.

a) (i) and (iv) (b) (ii) and (iii)

(c) (i) and (ii) (d) (iii) and (iv)

Q.

Question 9

Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?

(i) It is an endothermic reaction
(ii) It is an exothermic reaction
(iii) The pH of the resulting solution will be more than seven
(iv) The pH of the resulting solution will be less than seven

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

Q.

Question 9

Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?

(i) It is an endothermic reaction
(ii) It is an exothermic reaction
(iii) The pH of the resulting solution will be more than seven
(iv) The pH of the resulting solution will be less than seven

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

Q.

(a) Equal volumes of hydrogen and chlorine are exposed to diffused sunlight to prepare

(i) hydrogen chloride

(ii) water

(iii) sodium hydroxide

(iv) hydrochloric acid

(b) The metal which reacts with cold water to produce hydrogen is

(i) magnesium

(ii) aluminium

(iii) calcium

(iv) iron

(c) In metal reactivity series the more reactive metals are at

(i) top

(ii) bottom

(iii) middle

(iv) none

(d) Hydrogen is responsible for producing

(i) heat and light

(ii) hydrogenated oil

(iii) fertilizers

(iv) all of the above

(e) Hydrogen is

(i) combustible

(ii) non-combustible

(iii) supporter of combustion

(iv) neither supporter nor combustible

(f) Water gas is a mixture of

(i) carbon monoxide and oxygen

(ii) carbon monoxide and hydrogen

(iii) hydrogen and oxygen

(iv) hydrogen and nitrogen

Q. Question 27.
Which of the following is/are true when HCl(g) is passed through water?
(i) It does not ionise in the solution as it is a covalent compound.
(ii) It ionises in the solution.
(iii) It gives both hydrogen and hydroxyl ion in the solution.
(iv) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule.

(a) (i) only
(b) (iii) only
(c) (ii) and (iv)
(d) (iii) and (iv)

Q. Question 27.
Which of the following is/are true when HCl(g) is passed through water?
(i) It does not ionise in the solution as it is a covalent compound.
(ii) It ionises in the solution.
(iii) It gives both hydrogen and hydroxyl ion in the solution.
(iv) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule.

(a) (i) only
(b) (iii) only
(c) (ii) and (iv)
(d) (iii) and (iv)