Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
The inexhaustible source of energy of the stars is due to
In the process of electroplating a utensil with zinc,
Consider the following statements:
If there were no phenomenon of capillarity
1. It would be difficult to use a kerosene lamp.
2. One would not be able to use a straw to consume a soft drink.
3. the blotting paper would fail to function.
4. the big trees that we see around would not have grown on the earth.
Which of the statements given above are correct?
What is “ Kiss of death” ?
Consider the following statements:
Assertion (A): LPG is a pollution free vehicular fuel.
Reason (R): Plying of CNG fuelled-buses is recommended for metropolitan cities in India.
While tinning of brass utensils, the ammonium chloride powder used to clean the hot utensil produces fumes of
Domestic cooking gas consists of mostly
Which of the following substances is/are ozone depleting?
Select the correct answer from the codes given below:
1. Chlorofluorocarbons
2. Halons
3. Carbon tetrachloride
Acid rains is caused due to emission of which of the following into the atmosphere?
Living in the atmosphere of CO is dangerous because it
The order of appearance of the following with increasing temperature during the refining of crude oil is
A sample of chloroform before using as an anaesthetic, is tested by
When soggy biscuits are kept inside the fridge for sometime they become crisp because
Helium is preferred to hydrogen in air balloons because it
The difference between a nuclear reactor and atomic bomb is that
H2O is liquid and H2S is a gas because
Which one of the following statements is not true about cosmic rays?
Biogas mainly consists of
Hydrofluoric acid is not kept in glass bottles because it reacts with
Consider the following statements and select the correct code.
Assertion (A): A chemical reaction becomes faster at higher temperature.
Reason (R): At higher temperature, molecular motion becomes more rapid.
Which one of the following pairs is correctly matched?
What is the role of ultraviolet (UV) radiation in the water purification system?
1. It inactivates / kills the harmful micro- organisms in water.
2. It removes all the undesirable odours from the water.
3. It quickens the sedimentation of solid particles and improves the clarity of water.
Which of the statements given above is/are correct?
Hydrogen bomb is based on the principle of