Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Chemistry

Which of the following statements are correct about solid catalyst?

(i) Same reactants may give different product by using different catalysts.

(ii) Catalyst does not change ∆H of reaction.

(iii) Catalyst is required in large quantities to catalyse reactions.

(iv) Catalytic activity of a solid catalyst does not depend upon the strength of chemisorption.

Why is desorption important for a substance to act as good catalyst?

How does a solid catalyst enhance the rate of combination of gaseous molecules?

Do the vital functions of the body such as digestion get affected during fever? Explain your answer.

What do you understand by shape selective catalysis? Why are zeolites good shape selective catalysts?

In the extraction of copper from its sulphide ore, the metal is formed by the reduction of \[\ce{Cu2O}\] with ______.

In the metallurgy of aluminium ______.

Choose the correct option of temperature at which carbon reduces \[\ce{FeO}\] to iron and produces \[\ce{CO}\].

Below point ‘A’ \[\ce{FeO}\] can ______.

For the reduction of \[\ce{FeO}\] at the temperature corresponding to point D, which of the following statements is correct?

For the metallurgical process of which of the ores calcined ore can be reduced by carbon?

(i) Haematite

(ii) Calamine

(iii) Iron pyrites

(iv) Sphalerite

Wrought iron is the purest form of iron. Write a reaction used for the preparation of wrought iron from cast iron. How can the impurities of sulphur, silicon and phosphorus be removed from cast iron?

How is copper extracted from low grade copper ores?

The purest form of iron is prepared by oxidising impurities from cast iron in a reverberatory furnace. Which iron ore is used to line the furnace? Explain by giving reaction.

The mixture of compounds A and B is passed through a column of \[\ce{Al2O3}\] by using alcohol as eluant. Compound A is eluted in preference to compound B. Which of the compounds A or B, is more readily adsorbed on the column?

Why is sulphide ore of copper heated in a furnace after mixing with silica?

Write down the reactions taking place in Blast furnace related to the metallurgy of iron in the temperature range 500-800 K.

Explain the following:

\[\ce{CO2}\] is a better reducing agent below 710 K whereas \[\ce{CO}\] is a better reducing agent above 710 K.

Explain the following:

Generally sulphide ores are converted into oxides before reduction.

Explain the following:

Silica is added to the sulphide ore of copper in the reverberatory furnace.