Other Chemistry · JEE Main previous year questions

Which of the oxide groups among the following cannot be reduced by carbon?

1. A.$\mathrm{C}{\mathrm{u}}_2\mathrm{O},\mathrm{Sn}{\mathrm{O}}_2$
2. B.$\mathrm{CaO},{\mathrm{K}}_2\mathrm{O}$
3. C.$\mathrm{PbO},\mathrm{F}{\mathrm{e}}_3{\mathrm{O}}_4$
4. D.$\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3,\mathrm{ZnO}$

Among the following which is the best description of water in the solid phase?

1. A.Covalent solid
2. B.Molecular solid
3. C.Ionic solid
4. D.Network solid

Ionisation energy of $\mathrm{H}{\mathrm{e}}^{+}$ is $19.6\times 10^{-18}\mathrm{J}\mathrm{ato}{\mathrm{m}}^{-1}$. The energy of the first stationary state ($n=1$) of $\mathrm{L}{\mathrm{i}}^{2+}$ is

1. A.$4.41\times 10^{-16}\mathrm{J}\mathrm{ato}{\mathrm{m}}^{-1}$
2. B.$-4.41\times 10^{-17}\mathrm{J}\mathrm{ato}{\mathrm{m}}^{-1}$
3. C.$-2.2\times 10^{-15}\mathrm{J}\mathrm{ato}{\mathrm{m}}^{-1}$
4. D.$8.82\times 10^{-17}\mathrm{J}\mathrm{ato}{\mathrm{m}}^{-1}$

Three reactions involving ${\mathrm{H}}_2\mathrm{P}{\mathrm{O}}_4^{-}$ are given below : (i) ${\mathrm{H}}_3\mathrm{P}{\mathrm{O}}_4+{\mathrm{H}}_2\mathrm{O}\to {\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{H}}_2\mathrm{P}{\mathrm{O}}_4^{-}$ (ii) ${\mathrm{H}}_2\mathrm{P}{\mathrm{O}}_4^{-}+{\mathrm{H}}_2\mathrm{O}\to \mathrm{HP}{\mathrm{O}}_4^{2-}+{\mathrm{H}}_3{\mathrm{O}}^{+}$ (iii) ${\mathrm{H}}_2\mathrm{P}{\mathrm{O}}_4^{-}+\mathrm{O}{\mathrm{H}}^{-}\to {\mathrm{H}}_3\mathrm{P}{\mathrm{O}}_4+{\mathrm{O}}^{2-}$ In which of the above does ${\mathrm{H}}_2\mathrm{P}{\mathrm{O}}_4^{-}$ act as an acid?

1. A.(ii) only
2. B.(i) and (ii)
3. C.(iii) only
4. D.(i) only

In aqueous solution the ionization constants for carbonic acid are ${\mathrm{K}}_1=4.2\times 10^{-7}$ and ${\mathrm{K}}_2=4.8\times 10^{-11}$ Select the correct statement for a saturated 0.034 M solution of the carbonic acid.

1. A.The concentration of $\mathrm{C}{\mathrm{O}}_3^{2-}$ is 0.034 M.
2. B.The concentration of $\mathrm{C}{\mathrm{O}}_3^{2-}$ is greater than that of $\mathrm{HC}{\mathrm{O}}_3^{-}$
3. C.The concentration of ${\mathrm{H}}^{+}$ and $\mathrm{HC}{\mathrm{O}}_3^{-}$ are approximately equal.
4. D.The concentration of ${\mathrm{H}}^{+}$ is double that of $\mathrm{C}{\mathrm{O}}_3^{2-}$.

The correct order of $E_{M^{2+}/M}^o$ values with negative sign for the four successive elements Cr, Mn, Fe and Co is :

1. A.$\mathrm{Mn}>\mathrm{Cr}>\mathrm{Fe}>\mathrm{Co}$
2. B.$\mathrm{Cr}>\mathrm{Fe}>\mathrm{Mn}>\mathrm{Co}$
3. C.$\mathrm{Fe}>\mathrm{Mn}>\mathrm{Cr}>\mathrm{Co}$
4. D.$\mathrm{Cr}>\mathrm{Mn}>\mathrm{Fe}>\mathrm{Co}$

Biuret test is not given by

1. A.carbohydrates
2. B.polypeptides
3. C.urea
4. D.proteins

1. A.$B>C>A$
2. B.$B>A>C$
3. C.$C>B>A$
4. D.$A>B>C$

1. A.nitrobenzene and fluorobenzene
2. B.phenol and benzene
3. C.benzene diazonium chloride and fluorobenzene
4. D.nitrobenzene and chlorobenzene

Calculate the wavelength (in nanometer) associated with a proton moving at $1.0\times 10^3\mathrm{m}{\mathrm{s}}^{-1}$ (Mass of $\mathrm{proton}=1.67\times 10^{-27}\mathrm{kg}$ and $\mathrm{h}=6.63\times 10^{-34}\mathrm{Js}$) :

1. A.$0.40\mathrm{nm}$
2. B.$2.5\mathrm{nm}$
3. C.$14.0\mathrm{nm}$
4. D.$0.032\mathrm{nm}$

In an atom, an electron is moving with a speed of $600m/s$ with an accuracy of $0.005\%$. Certainity with which the position of the electron can be located is ($\mathrm{h}=6.6\times 10^{-34}\mathrm{kg}{\mathrm{m}}^2{\mathrm{s}}^{-1}$, mass of electron, $e_m=9.1\times 10^{-31}\mathrm{kg}$)

1. A.$5.10\times 10^{-3}\mathrm{m}$
2. B.$1.92\times 10^{-3}\mathrm{m}$
3. C.$3.84\times 10^{-3}\mathrm{m}$
4. D.$1.52\times 10^{-4}\mathrm{m}$

In which of the following arrangements, the sequence is not strictly according to the property written against it

1. A.$\mathrm{C}{\mathrm{O}}_2<\mathrm{Si}{\mathrm{O}}_2<\mathrm{Sn}{\mathrm{O}}_2<\mathrm{Pb}{\mathrm{O}}_2$ : increasing oxidising power
2. B.$\mathrm{HF}<\mathrm{HCl}<\mathrm{HBr}<\mathrm{HI}$ : increasing acid strength
3. C.$\mathrm{N}{\mathrm{H}}_3<\mathrm{P}{\mathrm{H}}_3<\mathrm{As}{\mathrm{H}}_3<\mathrm{Sb}{\mathrm{H}}_3$ : increasing basic strength
4. D.$\mathrm{B}<\mathrm{C}<\mathrm{O}<\mathrm{N}$ : increasing first ionization enthalpy

The half life period of a first order chemical reaction is 6.93 minutes. The time required for the completion of 99% of the chemical reaction will be (log 2=0.301) :

1. A.230.3 minutes
2. B.23.03 minutes
3. C.46.06 minutes
4. D.460.6 minutes

Which of the following statements is incorrect regarding physisorption ?

1. A.It occurs because of van der Waals forces.
2. B.More easily liquefiable gases are adsorbed readily.
3. C.Under high pressure it results into multi molecular layer on adsorbent surface.
4. D.Enthalpy of adsorption ($\Delta H_{adsorption}$ ) is low and positive

Which of the following molecules/ions does not contain unpaired electrons?

1. A.${\mathrm{O}}_2^{2-}$
2. B.${\mathrm{B}}_2$
3. C.$N_2^{+}$
4. D.${\mathrm{O}}_2$

In which of the following molecules/ions are all the bonds not equal?

1. A.$\mathrm{Xe}{\mathrm{F}}_4$
2. B.$B{F}_4^{-}$
3. C.$\mathrm{S}{\mathrm{F}}_4$
4. D.$\mathrm{Si}{\mathrm{F}}_4$

Among the following mixtures, dipole-dipole as the major interaction, is present in

1. A.benzene and ethanol
2. B.acetonitrile and acetone
3. C.KCl and water
4. D.benzene and carbon tetrachloride

Which of the following chemical reactions depicts the oxidizing behaviour of ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$?

1. A.$\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4\to \mathrm{NaHS}{\mathrm{O}}_4+\mathrm{HCl}$
2. B.$2PC{\mathrm{l}}_5+{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4\to 2POC{\mathrm{l}}_3+2HCl+\mathrm{S}{\mathrm{O}}_2\mathrm{C}{\mathrm{l}}_2$
3. C.$2HI+{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4\to {\mathrm{I}}_2+\mathrm{S}{\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}$
4. D.$\mathrm{Ca}(\mathrm{OH}{)}_2+{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4\to \mathrm{CaS}{\mathrm{O}}_4+2{\mathrm{H}}_2\mathrm{O}$

The molar conductivities ${\wedge }_{NaOAc}^{\circ }$ and ${\wedge }_{HCl}^{\circ }$ and at infinite dilution in water at $25^{\circ }\mathrm{C}$ are 91.0 and $426.2\mathrm{Sc}{\mathrm{m}}^2/mol$ respectively. To calculate ${\wedge }_{HOAc}^{\circ }$, the additional value required is

1. A.${\wedge }_{H_{2}O}^{\circ }$
2. B.${\wedge }_{KCl}^{\circ }$
3. C.${\wedge }_{NaOH}^{\circ }$
4. D.${\wedge }_{NaCl}^{\circ }$

Which of the following statements is true?

1. A.${\mathrm{H}}_3\mathrm{P}{\mathrm{O}}_3$ is a stronger acid than ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_3$
2. B.In aqueous medium HF is a stronger acid than HCl
3. C.$\mathrm{HCl}{\mathrm{O}}_4$ is a weaker acid than $\mathrm{HCl}{\mathrm{O}}_3$
4. D.$\mathrm{HN}{\mathrm{O}}_3$ is a stronger acid than $\mathrm{HN}{\mathrm{O}}_2$

In $\mathrm{Fe}(\mathrm{CO}{)}_5$, the $\mathrm{Fe}-\mathrm{C}$ bond possesses :

1. A.$\pi$-character only
2. B.both $\sigma$ and $\pi$ characters
3. C.ionic character
4. D.$\sigma$-character

HBr reacts with $\mathrm{C}{\mathrm{H}}_2=\mathrm{CH}-\mathrm{OC}{\mathrm{H}}_3$ under anhydrous conditions at room temperature to give

1. A.$\mathrm{C}{\mathrm{H}}_3\mathrm{CHO}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{Br}$
2. B.$\mathrm{BrC}{\mathrm{H}}_2\mathrm{CHO}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{OH}$
3. C.$\mathrm{BrC}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-\mathrm{OC}{\mathrm{H}}_3$
4. D.${\mathrm{H}}_3\mathrm{C}-\mathrm{CHBr}-\mathrm{OC}{\mathrm{H}}_3$

The increasing order of the rate of HCN addition to compounds A – D is (A) HCHO (B) $\mathrm{C}{\mathrm{H}}_3\mathrm{COC}{\mathrm{H}}_3$ (C) $\mathrm{PhCOC}{\mathrm{H}}_3$ (D) PhCOPh

1. A.$\mathrm{A}<\mathrm{B}<\mathrm{C}<\mathrm{D}$
2. B.$\mathrm{D}<\mathrm{B}<\mathrm{C}<\mathrm{A}$
3. C.$\mathrm{D}<\mathrm{C}<\mathrm{B}<\mathrm{A}$
4. D.$\mathrm{C}<\mathrm{D}<\mathrm{B}<\mathrm{A}$

Which of the following oxides is amphoteric in character?

1. A.$\mathrm{CaO}$
2. B.${\mathrm{CO}}_2$
3. C.${\mathrm{SiO}}_2$
4. D.${\mathrm{SnO}}_2$

In which of the following arrangements the order is NOT according to the property indicated against it?

1. A.$\mathrm{Li}<\mathrm{Na}<\mathrm{K}<\mathrm{Rb}$ Increasing metallic radius
2. B.$\mathrm{I}<\mathrm{Br}<\mathrm{F}<\mathrm{Cl}$ Increasing electron gain enthalpy (with negative sign)
3. C.$\mathrm{B}<\mathrm{C}<\mathrm{N}<\mathrm{O}$ Increasing first ionization enthalpy
4. D.$\mathrm{A}{\mathrm{l}}^{3+}<\mathrm{M}{\mathrm{g}}^{2+}<\mathrm{N}{\mathrm{a}}^{+}<{\mathrm{F}}^{-}$ Increasing ionic size