CBSE Class 7 Chemistry (Demo)

Select the incorrect observation

Which of the following statement is/ are correct regarding dilution of concentrated sulphuric acid?

(i) Large volume of acid should be added to a small volume of water slowly.

(ii) Water should be added to acid in small volumes

(iii) The process involves release of a large amount of heat

(iv) Water should not be stirred

Match the following:

Which of the following represents a neutralization reaction?

Few pieces of metals are placed on copper sulphate solution. Then what will be the result after half an hour.

$$\mathrm{Al}_{2} \mathrm{O}_{3}+2 \mathrm{NaOH} \longrightarrow \longrightarrow+\mathrm{H}_{2} \mathrm{O}$$

Aluminium is used in the production of cooking utensils which of the following properties of aluminium is responsible for the occurrence.

(i) Good thermal conductivity

(ii) Brittle in nature

(iii) Ductility

(iv) The melting point is extremely high

Galvanisation is a technique for protecting iron from corrosion by coating it with a thin layer of

Which of the following is not an example of endothermic change?

Mist is an example of a

The valency electron of an element are responsible for which of the following

Select the incorrect statement

(i) Hydrogen gas turns lime water milky

(ii) Both rust formation and ice formation are chemical changes.

(iii) Both melting of butter and wax are physical changes.

(iv) curdling of milk is a chemical change.

Classify the incorrect process

Chromatography on pure substance. What would be the observation

You are given with liquid – liquid homogeneous mixture having 2 components. $$X$$ is having $$78^{\circ}$$ and compound $$B$$ is having $$100^{\circ}$$. Which of the following is used to separate the two liquid?

Select the incorrect statement

Which among the following is a liquid – solid homogeneous mixture

Which one of the following fruits contains ascorbic acid?

Why is organic matter added to the soil?

Which of the following substances can be used to soothe the discomfort brought on by wasp stings?

When dilute hydrochloric acid and a substance $$X$$ that can be used as an antacid are combined, a gas $$Y$$ is created that is used in fire extinguishers. Determine $$X$$ and $$Y$$.

When a man with stomach pain went to the doctor, the physician identified acidity. Which of the following would be the suitable remedy for him?

Which of the life cycle of lime is right

The gas which has rotten egg smell is

Which of the following gas is important for protein synthesis in plants.