CBSE Class X – Science Chemistry Exam (Full Syllabus)

Why are anti-oxidants added to fat and oil containing food items?

Identify the reducing agent in the following reactions: Fe₂O₃ + 3CO → 2Fe + 3CO₂

Mention whether it is physical or chemical changes: Sublimation of solid ammonium chloride

Dilute hydrochloric acid is added to granulated zinc taken in a test tube. The following observations are recorded. Designate the accurate observation:

Three beakers labelled as A, B and C, each containing 25 ml of water, were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in the case of beaker C, the temperature of the solution fell. Which one of the following statement(s) is (are) correct?

1. In beakers A and B, exothermic process has occurred.
2. In beakers A and B, endothermic process has occurred
3. In beaker C, exothermic process has occurred
4. In beaker C, endothermic process has occurred.

Calcium phosphate is present in tooth enamel. Its nature is:

To preserve tooth decay we are advised to brush our teeth regularly. The nature of the toothpaste commonly used is:

Sodium carbonate is a basic salt because it is a salt of:

Which of the following statements is accurate about an aqueous solution of an acid and a base?

1. Higher the pH, stronger the acid
2. Higher the pH, weaker the acid
3. Higher the pH, stronger the base
4. Lower the pH, weaker the base

The chemical used for cleaning swimming pools

Which of the following elements does not lose an electron with ease?

Arrange these elements in increasing order of their atomic radii

The formulae of chlorides of Eka-silicon the elements predicted by Mendeleev.

The number of groups in the Modern Periodic Table

Arrange the following elements in increasing order of their atomic radii:

Buckminsterfullerene is an allotropic form of:

The electronic configuration of an element is found to be 2, 4. How many bonds can one carbon atom form in a compound?

A saturated hydrocarbon undergoes complete combustion and burns with

Ethane is

The compounds have low melting and boiling points.

The composition of aqua-regia is:

When calcium metal is added to water, the gas evolved does not catch fire but the same gas evolved on adding potassium metal to water catches fire.

Give the formula of the stable binary compounds that would be formed by the combination of following pair of elements: Li and O₂

Give the formula of the stable binary compounds that would be formed by the combination of following pair of elements: Al and Cl₂

Name one non-metal that exist in liquid state at room temperature.