Mole | MCQs

Explanation

Explanation

Diffusion is the natural movement of particles from an area of higher concentration to lower concentration without external force.

It occurs in gases, liquids, and even solids to some extent.

Explanation

Explanation

Explanation

Both CS₂ (carbon disulfide) and SO₃ (sulfur trioxide) have zero dipole moment.

Note….: Here CS 2 and SO3 options are correct. However, FPSC did not give a choice of both A and B.

Explanation

O₂ (oxygen molecule) is paramagnetic because it has unpaired electrons in its molecular orbitals.

According to Molecular Orbital Theory (MOT), the electronic configuration of O₂ reveals 

There are two unpaired electrons in the π* anti-bonding orbitals, which are responsible for its paramagnetic properties.

Hybridization and resonance do not directly explain the presence of unpaired electrons in this context.

Explanation

Iodine heptafluoride (IF₇) has a pentagonal bipyramidal structure.

In this geometry, iodine is surrounded by seven fluorine atoms:

• five fluorines are arranged in a plane forming a pentagon,
• and the other two fluorines are positioned above and below this plane,
• forming the axial positions.

This arrangement minimizes electron pair repulsion around the iodine atom.

Explanation

Isopropyl alcohol is used to precipitate DNA during extraction from sources like bananas or strawberries.

When added to the mixture, DNA becomes visible as it separates out in the cold alcohol layer.

Explanation

RNA contains Uracil instead of Thymine, which is found in DNA.

The four bases in RNA are Adenine (A), Uracil (U), Guanine (G), and Cytosine (C).

Explanation

A palindromic sequence reads the same forwards and backwards.

Given the sequence "CTTAAG", the complementary palindromic sequence is "GAATTC". 

In DNA, A pairs with T and C pairs with G. 

When reading the complementary strand from 5' to 3', the sequence becomes "GAATTC", which is the same as the original sequence read from 5' to 3'.