Combustion And ...

Directions: Read the statements given below and select the correct option.

Statement 1: Combustion is a chemical process in which a substance reacts with oxygen to give out heat and light.
Statement 2: Heat and light are produced in the sun due to combustion.

Which of the following options correctly defines calorific value of a fuel?

Observe the image given below and answer the question that follows.



Which of the following in an incorrect statement?

Analyse the two statements given below and select the correct option.

Statement I: Fuel are energy reserves and this energy is released by the process of combustion.
Statement II: Combustion is the process of burning the substance in the presence of a sufficient quantity of oxygen.

Observe the given flow chart and the statements that follow.



I. W and X are the components of water gas.
II. W, X and Y are the components of coal gas.
III. W is a rocket fuel.
IV. Z is a domestic fuel.

Which of the following options is the correct identification of W, X, Y and Z?

Which of the following options regarding burning of coal is correct?

Combustion of fuels is

In which of the following cases is the use of water as a fire extinguisher inappropriate?

I. In an electrical appliance shop
II. In a newspaper factory
III. In a furniture house

What happens when water is heated in a paper cup?

Water is used to extinguish fire because it

Directions: Read the two statements given below and select the correct option accordingly.

Statement I: Air supports the combustion process.
Statement II: Air is a homogeneous mixture of gases with 78% nitrogen and nearly 21% oxygen.

Consider the following statements about the combustion of fuels:

(i) Combustion of fuels occurs in the presence of oxygen.
(ii) Combustion is a slow process.
(iii) It requires an external source of ignition.
(iv) This process usually takes place at room temperature.

Which of the above statements are not correct?

Which among the following are released during the process of combustion of fuels?

Match the combustion processes in Column I with the types of combustion in Column II.

Which of the following chemical substances are the components of a matchstick head and which are present on the striking surface (Side of the match box)?

(I) Antimony trisulphide
(II) Potassium chlorate
(III) Red phosphorus
(IV) Powdered glass

Which of the following fuels has the highest calorific value?

A good fuel should have

Study the dichotomous key and identify the correct statements about W, X and Y:

I. (i) A fuel that does not burn with a flame
(ii) A fuel that burns with a flame Go to II
II. (i) It is a gaseous fuel.
(ii) It is a solid fuel.

A. W may be wood or kerosene.
B. X may be used for cooking.
C. Y can produce a luminous flame.
D. Y vaporises on heating.
E. X may be used in automobiles.

Match the following:

In the flow chart given below, X and Y represent the type of combustion and P and Q represent the type of flame.



Select the option which is the correct identification of X, Y, P and Q.