H2O is liquid and H2S is a gas because
The blue colour of water in the sea. What is the reason behind the phenomenon?
A sample of chloroform before using as an anaesthetic, is tested by
Living in the atmosphere of CO is dangerous because it
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?
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.
In cold weather, aquatic animals survive even when water to the top layer of the lake freezes into ice because
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
Hydrogen bomb is based on the principle of
Acid rains is caused due to emission of which of the following into the atmosphere?
Which one of the following pairs is correctly matched?
While tinning of brass utensils, the ammonium chloride powder used to clean the hot utensil produces fumes of
What is “ Kiss of death” ?
Hydrofluoric acid is not kept in glass bottles because it reacts with
Biogas mainly consists of
Domestic cooking gas consists of mostly
The difference between a nuclear reactor and atomic bomb is that
Which one of the following statements is not true about cosmic rays?
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?
Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
The order of appearance of the following with increasing temperature during the refining of crude oil is
In the process of electroplating a utensil with zinc,
When soggy biscuits are kept inside the fridge for sometime they become crisp because
The inexhaustible source of energy of the stars is due to
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.