CBSE Class X – Science Chemistry + Biology + Physics Exam (Full Syllabus)

Decomposition reaction can be defined as the reaction which involves decomposition of one compound to more than one substance. Endothermic reactions require heat energy to form products.

When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide is obtained and the sulphuric acid. So formed remains in the solution.

When a small amount of acid such as hydrochloric acid is added to water, individual ions of the acid are dissociated This process is known as ionisation.

When pieces of copper metal are kept immersed in silver sulphate solution for some time, the solution moderately becomes blue and a shiny greyish-white deposit of silver metal is formed on copper strip

Ethanoic acid when treated with baking soda (Sodium hydrogencarbonate) gives brisk effervescence of Carbon dioxide gas.

A cation is formed by loss electrons from the atom of an element which acquires positive charge due to the presence of greater number of protons as compared to that of electrons.

Carbon is an essential constituent of all organic compounds and it belongs to group 14.

Na and Mg belong to the sameperiod, whereas Na and K are in the same group.In a group from top to bottom, the atomic radius increases, whereas it decreases in a period from left to right. Hence, the order would be K ɳ Na ɳ Mg and K ɳ Ca ɳ Mg

Fishes have only two chambers to their hearts, and the blood is pumped to the gills, is oxygenated there, and passes directly to the rest of the body. Thus, blood goes only once through the heart in the fsh during one cycle of passage through the body.

Steps of photosynthesis are as follows: (i) Absorption of light energy by chlorophyll. (ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen. (iii) Reduction of carbon dioxide to carbohydrates.

Umbilical cord is responsible for exchange of nutrients, oxygen and waste products between the embryo and the mother’s body .

Radish and carrot represent the correct homologous structures because both have similar design or structure, though both are of different species.

2 minutes (due to advanced sunrise) + 2 minutes (due to delayed sunset)

Total power used, P = P1 + P1 = 1500 + 500 = 2000 W.Current drawn from the supply,

Only option_x000D__x000D_-> {The pattern of the magnetic feld associated with the solenoid is diferent from the pattern of the magnetic field around a bar magnet }_x000D__x000D_is incorrect because the pattern of magnetic fields due to solenoid and bar magnet is almost same.