JEE MAIN - Chemistry (2022 - 26th July Evening Shift)
1
Hemoglobin contains $$0.34 \%$$ of iron by mass. The number of Fe atoms in $$3.3 \mathrm{~g}$$ of hemoglobin is
(Given: Atomic mass of Fe is $$56 \,\mathrm{u}, \mathrm{N}_{\mathrm{A}}=6.022 \times 10^{23} \mathrm{~mol}^{-1}$$.)
Answer
(C)
$$1.21 \times 10^{20}$$
2
Arrange the following in increasing order of their covalent character.
A. $$\mathrm{CaF}_{2}$$
B. $$\mathrm{CaCl}_{2}$$
C. $$\mathrm{CaBr}_{2}$$
D. $$\mathrm{CaI}_{2}$$
Choose the correct answer from the options given below.
Answer
(B)
A < B < C < D
3
Class XII students were asked to prepare one litre of buffer solution of $$\mathrm{pH} \,8.26$$ by their Chemistry teacher: The amount of ammonium chloride to be dissolved by the student in $$0.2\, \mathrm{M}$$ ammonia solution to make one litre of the buffer is :
Molar mass of $$\mathrm{NH}_{3}=17 \mathrm{~g} \mathrm{~mol}^{-1}$$
Molar mass of $$\mathrm{NH}_{4} \mathrm{Cl}=53.5 \mathrm{~g} \mathrm{~mol}^{-1}$$ )
Answer
(C)
107.0 g
4
At $$30^{\circ} \mathrm{C}$$, the half life for the decomposition of $$\mathrm{AB}_{2}$$ is $$200 \mathrm{~s}$$ and is independent of the initial concentration of $$\mathrm{AB}_{2}$$. The time required for $$80 \%$$ of the $$\mathrm{AB}_{2}$$ to decompose is
Given: $$\log 2=0.30$$ $$\quad \log 3=0.48$$
Answer
(C)
467 s
5
The metal complex that is diamagnetic is (Atomic number: $$\mathrm{Fe}, 26 ; \mathrm{Cu}, 29)$$
Given below are two statements: one is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$.
Assertion A: Phenolphthalein is a $$\mathrm{pH}$$ dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium.
Reason R: Phenolphthalein is a weak acid. It doesn't dissociate in basic medium.
In the light of the above statements, choose the most appropriate answer from the options given below.
Answer
(C)
A is true but R is false.
13
Consider an imaginary ion $${ }_{22}^{48} \mathrm{X}^{3-}$$. The nucleus contains '$$a$$'% more neutrons than the number of electrons in the ion. The value of 'a' is _______________. [nearest integer]
The elevation in boiling point for 1 molal solution of non-volatile solute A is $$3 \mathrm{~K}$$. The depression in freezing point for 2 molal solution of $$\mathrm{A}$$ in the same solvent is 6 $$K$$. The ratio of $$K_{b}$$ and $$K_{f}$$ i.e., $$K_{b} / K_{f}$$ is $$1: X$$. The value of $$X$$ is [nearest integer]
Answer
1
16
$$20 \mathrm{~mL}$$ of $$0.02\, \mathrm{M}$$ hypo solution is used for the titration of $$10 \mathrm{~mL}$$ of copper sulphate solution, in the presence of excess of KI using starch as an indicator. The molarity of $$\mathrm{Cu}^{2+}$$ is found to be ____________ $$\times 10^{-2} \,\mathrm{M}$$. [nearest integer]
Given : $$2 \,\mathrm{Cu}^{2+}+4 \,\mathrm{I}^{-} \rightarrow \mathrm{Cu}_{2} \mathrm{I}_{2}+\mathrm{I}_{2}$$
The spin-only magnetic moment value of the compound with strongest oxidizing ability among $$\mathrm{MnF}_{4}, \mathrm{MnF}_{3}$$ and $$\mathrm{MnF}_{2}$$ is ____________ B.M. [nearest integer]
Answer
5
18
Total number of isomers (including stereoisomers) obtained on monochlorination of methylcyclohexane is ___________.
Answer
12
19
A $$100 \mathrm{~mL}$$ solution of $$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{MgBr}$$ on treatment with methanol produces $$2.24 \mathrm{~mL}$$ of a gas at STP. The weight of gas produced is _____________ mg. [nearest integer]