When sodium hydrogen carbonate is added to ethanoic acid a gas evolves. Consider the following statements about the gas evolved?

(A) It turns lime water milky.

(B) It is evolved with a brisk effervescence.

(C) It has a smell of burning sulphur.

(D) It is also a by-product of respiration. The correct statements are:

Which one of the following is responsible for the sustenance of underground water?

Incomplete combustion of coal and petroleum:

(A) increases air pollution.

(B) increases efficiency of machines.

(C) reduces global warming

(D) produce poisonous gases

The correct option is :

When a small amount of acid is added to water, the phenomena which occur are :

(A) Dilution

(B) Neutralisation

(C) Formation of H₃ O⁺ ions

(D) Salt formation The correct statements are :

A real image is formed by the light rays after reflection or refraction when they :

(A) actually meet or intersect with each other.

(B) actually converge at a point.

(C) appear to meet when they are produced in the backward direction.

(D) appear to diverge from a point. Which of the above statements are correct?

A. (A) and (D) B. (B) and (D)

C. (A) and (B) D. (B) and (C)

OR

Consider the following properties of virtual images:

(A) cannot be projected on the screen

(B) are formed by both concave and convex lens

(C) are always erect

(D) are always inverted The correct properties are :

A. (A) and (D) B. (A) and (B)

C. (A), (B) and (C) D. (A), (B) and (D)