Biomolecules — Chemistry STD 12 Science — Question

On the basis of lanthanoid contraction, explain the following:
Radii of 4d and 5d block elements.

With reference to which classification has the statement, “ranitidine is an antacid” been given?

How will you convert?
Benzene into aniline.

Note: In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion and reason both are incorrect statements.
5. Assertion is wrong statement but reason is correct statement.

Assertion: When NaCl is added to water a depression in freezing point is observed.
Reason: The lowering of vapour pressure of a solution causes depression in the freezing point.

How does the ordinary light differ from the plane polarised light?

Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.
m–BrC₆H₄NH₂

Arrange the following compound in increasing order of their reactivity in nucleophilic addition reaction.

Ethanal, Propanal, Propanone, Butanone.

[Hint: Consider steric effect and electronic effect.]

Why is glycol and water mixture used in car radiators in cold countries?

What is the necessity to use a salt bridge in a Galvanic cell?

In Kolbe’s reaction, instead of phenol, phenoxide ion is treated with carbon dioxide. Why?