List of top Chemistry Questions

An element X reacts with oxygen and forms oxide of X which turns red litmus to blue. The element X is a :

When chlorine gas is passed in lime water, it forms chemical compound 'M' (main constituent of bleaching powder) and 'N' (used for bleaching in textile industry). Identify the correct option.

Brine is an :

Match Column-I (Different substances) with Column-II (pH values) and choose the correct option from the codes given below :

Tooth-enamel is made up of :

Which one of the following does not have water of crystallization?

Which of the following is known as 'Slaked Lime'?

Why a mild base like magnesium hydroxide is used during indigestion?

You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. Which of them will turn red litmus to blue?

What does calcium oxide produce when it reacts vigorously with water?

All of the following acids dissociate completely in water, except :

Acetic acid was added to a solid X kept in a test tube. A colourless, odourless gas Y was evolved. The gas was passed through lime water, which turned milky. It was concluded that:

What happens when a solution of an acid is mixed with a solution of a base in a test tube?
(i) The temperature of the solution increases.
(ii) The temperature of the solution decreases.
(iii) The temperature of the solution remains the same.
(iv) Salt formation takes place.

Sodium salt of acid present in vinegar is an example of :

Which of the following is formed after a few days of whitewashing and gives a shiny finish to the wall?

When a copper vessel is exposed to moist air for long, it acquires a dull green coating. The green material is a mixture of:

During electrolysis of water, identify the correct combination.

The balancing of chemical equations is in accordance with :

Endothermic reactions are those in which :

A white coloured compound 'X' heated strongly to form white powder of 'PbO' along with two gases 'Y' : brown in colour, 'Z' : colorless. Identify 'X', 'Y', 'Z'.

Which statements is/are correct?
Statement-I : Soap does not form foam easily with hard water.
Statement-II : Hard soaps are sodium or potassium salt of sulphonic acids.
Statement-III : Deuterium oxide (\(\text{D}_2\text{O}\)) is called as hard water.

Choose incorrect combination :

The odour of acetic acid resembles that of :

Which of the following will give a pleasant smell of ester when heated with ethanol and a small quantity of sulphuric acid?

Which is one of the products of chlorination of methane in the presence of sunlight?