Chemistry

Based on the passage, which of the following best captures the meaning of HIF, or hypoxia-inducible factor?

A. It is a protein that increases inside the cell when the oxygen levels fall, helping the cell survive.
B. It inhibits oxygen carrying process in the body as the oxygen level increases inside the cell.
C. It enables cells to adapt quickly to the changing environment and helps in its survival.
D. It regulates the amount of oxygen available to the cell and the body during exercise.

Based on the passage, which of the following best captures the meaning of HIF, or hypoxia-inducible factor?

A. It is a protein that increases inside the cell when the oxygen levels fall, helping the cell survive.
B. It inhibits oxygen carrying process in the body as the oxygen level increases inside the cell.
C. It enables cells to adapt quickly to the changing environment and helps in its survival.
D. It regulates the amount of oxygen available to the cell and the body during exercise.

Assertion (A): Silicones are water repelling in nature.

Reason (R): Silicones are organosilicon polymers, which have (-R₂SiO-) as repeating unit.

(A) Both A and R are true and R is the correct explanation of A.

(B) Both A and R are true but R is not the correct explanation of A.

(C) Both A and R are not correct. 

(D) A is not correct but R is correct.

Assertion (A): If aluminium atoms replace a few silicon atoms in three dimensional network of silicon dioxide, the overall structure acquires a negative charge.

Reason (R): Aluminium is trivalent while silicon is tetravalent.

(A) Both A and R are true and R is the correct explanation of A.

(B) Both A and R are true but R is not the correct explanation of A.

(C) Both A and R are not correct.

(D) A is not correct but R is correct.

Match the species given in Column I with the hybridisation given in Column II.

Match the species given in Column I with properties given in Column II.

Match the species given in Column I with the properties mentioned in Column II.

Identify the correct resonance structures of carbon dioxide from the ones given below:

(A) O−C≡O

(B) O=C=O

(C) −O≡C−O⁺

(D) −O−C≡O⁺

Which of the following statements are correct? Answer on the basis of figure.

(A) The two bridged hydrogen atoms and the two boron atoms lie in one plane. 

(B) Out of six B - H, bonds two bonds can be described in terms of 3 centre 2-electron bonds.

(C) Out of six B- H bonds four B- H bonds can be described in terms of 3 centre 2 electron bonds.

(D) The four terminal B - H bonds are two centre-two electron regular bonds.

Which of the following statements are correct?

(A) Fullerenes have dangling bonds.

(B) Fullerenes are cage-like molecules.

(C) Graphite is thermodynamically most stable allotrope of carbon.

(D) Graphite is slippery and hard and therefore used as a dry lubricant in machines.