Class 12th

This is a multiple choice answer as classified in NCERT Exemplar

Correct option is (ii) and (iv)

Tetrahedral geometry characterises the structure of a white phosphorus molecule.

Phosphorus has a valency of 5, and there are four phosphorus atoms in total. As a result, there will be a total of 4*5=20 valence electrons.

As a result, each P atom will have one lone pair of electrons, and each covalent bond (two electrons) will be established.

In a molecule of white phosphorus, there will be four lone pairs of electrons and six P-P single bonds in total.

This is a multiple choice answer as classified in NCERT Exemplar

Correct option is (ii), (iii)

MI  >  MBr  >  MCl  >  MF is an iconic character of metal halide

F₂ >  Cl₂ >  Br₂ > I₂ is a bond dissociation enthalpy

This is a Short Answer Type Question as classified in NCERT Exemplar

Sol:

$\begin{array}{l}Given that, A = \left\{a,b,c,d\right\}\hfill \end{array}$

$\begin{array}{l}and f = \left\{\left(a,b\right),\left(b,d\right),\left(c,a\right),\left(d,c\right)\right\}\hfill \end{array}$

$\begin{array}{l}{f}^{-1}= \left\{\left(b,a\right),\left(d,b\right),\left(a,c\right),\left(c,d\right)\right\}\hfill \end{array}$

This is a Short Answer Type Question as classified in NCERT Exemplar

Sol:

$\begin{array}{l}\begin{array}{l}f\left(x\right) = 2x - 3\hfill \end{array}\end{array}$

$\begin{array}{l}\begin{array}{l}Let f\left(x\right)= y = 2x – 3\hfill \end{array}\\ \Rightarrow y+3=2x\Rightarrow x=\frac{y\text{?}+3}{2}\\ \therefore f^{-1}(y)=\frac{y+3}{2}0r{f}^{-1}(x)=\frac{x+3}{2}\end{array}$

This is a multiple choice answer as classified in NCERT Exemplar

Correct option is (i) and (iii)

6NaOH+3Cl₂ → 5NaCl+NaClO₃+3H₂O

Chlorine gas oxidation number ranges from 0 to –1 to 0 to +5.

This is a Short Answer Type Question as classified in NCERT Exemplar

Sol:

$\begin{array}{l}f(x)=2x+1andg(x)=x^2-2\\ \therefore gof=g\left[f(x)\right]\\ ={\left[2x+1\right]}^2-2\\ =4x^2+4x+1-2\\ =4x^2+4x-1\\ Hence,gof=4x^2+4x-1.\end{array}$

This is a Short Answer Type Question as classified in NCERT Exemplar

Sol:

This is a multiple choice answer as classified in NCERT Exemplar

Correct option is (ii)

BrO₂^- (35+2*8+1=52) and BrF₂⁺  (35+2*9−1=52)

52 electrons are present in both 

This is a Short Answer Type Question as classified in NCERT Exemplar

Sol: R = { (a, a), (b, c), (a, b)}.

To make R as reflexive we must add (b, b) and (c, c) to R. Also, to make R as transitive we must add

(a, c) to R.

So, minimum number of ordered pair is to be added are (b, b), (c, c), (a, c).

This is a multiple choice answer as classified in NCERT Exemplar

Correct option is (iii)

The ability of a substance to be decreased is known as its reduction potential. As the substance's reduction potential rises, so does its power to reduce. It signifies the chemical's oxidising power (the ability of the material to cause other substances to lose electrons, which is known as oxidising power) grows.

As a result, the oxidising power is listed in decreasing order BrO₄^-  >  IO₄^-  >  ClO₄^-