Other Chemistry · JEE Main previous year questions

Order of Covalent bond; A. $\mathrm{KF}>\mathrm{KI};\mathrm{LiF}>\mathrm{KF}$ B. $\mathrm{KF}<\mathrm{KI};\mathrm{LiF}>\mathrm{KF}$ C. $\mathrm{SnC}{\mathrm{l}}_4>\mathrm{SnC}{\mathrm{l}}_2;\mathrm{CuCl}>\mathrm{NaCl}$ D. $\mathrm{LiF}>\mathrm{KF};\mathrm{CuCl}<\mathrm{NaCl}$ E. $\mathrm{KF}<\mathrm{KI};\mathrm{CuCl}>\mathrm{NaCl}$ Choose the correct answer from the options given below :

1. A.B, C only
2. B.A, B only
3. C.C, E only
4. D.B, C, E only

$5\mathrm{g}$ of $\mathrm{NaOH}$ was dissolved in deionized water to prepare a $450\mathrm{mL}$ stock solution. What volume (in $\mathrm{mL}$) of this solution would be required to prepare $500\mathrm{mL}$ of $0.1\mathrm{M}$ solution? ____ Given : Molar Mass of Na, O and H is 23, 16 and $1\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ respectively

If wavelength of the first line of the Paschen series of hydrogen atom is 720 nm, then the wavelength of the second line of this series is _________ nm. (Nearest integer)

The number of s-electrons present in an ion with 55 protons in its unipositive state is

1. A.10
2. B.9
3. C.12
4. D.8

${\mathrm{K}}_2\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7$ paper acidified with dilute ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ turns green when exposed to :

1. A.Sulphur dioxide
2. B.Sulphur trioxide
3. C.Hydrogen sulphide
4. D.Carbon dioxide

1. A.a only
2. B.Both a and c
3. C.c only
4. D.b only

Correct statement is :

1. A.An average human being consumes more food than air
2. B.An average human being consumes 100 times more air than food
3. C.An average human being consumes nearly 15 times more air than food
4. D.An average human being consumes equal amount of food and air

Sum of $\pi$-bonds present in peroxodisulphuric acid and pyrosulphuric acid is ____

Which of the following pair of molecules contains an odd electron molecule and an expanded octet molecule?

1. A.$\mathrm{BC}{\mathrm{l}}_3$ and $\mathrm{S}{\mathrm{F}}_6$
2. B.$\mathrm{NO}$ and ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$
3. C.$\mathrm{S}{\mathrm{F}}_6$ and ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$
4. D.$\mathrm{BC}{\mathrm{l}}_3$ and $\mathrm{NO}$

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

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

$100\mathrm{mL}$ of $5\%(w/v)$ solution of $\mathrm{NaCl}$ in water was prepared in $250\mathrm{mL}$ beaker. Albumin from the egg was poured into $\mathrm{NaCl}$ solution and stirred well. This resulted in a/an :

1. A.Lyophilic sol
2. B.Lyophobic sol
3. C.Emulsion
4. D.Precipitate

Which among the following pairs has only herbicides?

1. A.Aldrin and Dieldrin
2. B.Sodium chlorate and Aldrin
3. C.Sodium arsinate and Dieldrin
4. D.Sodium chlorate and sodium arsinite

In liquation process used for tin (Sn), the metal :

1. A.is reacted with acid.
2. B.is dissolved in water.
3. C.is brought to molten form which is made to flow on a slope.
4. D.is fused with NaOH

Identify the incorrect statement from the following.

1. A.A circular path around the nucleus in which an electron moves is proposed as Bohr's orbit.
2. B.An orbital is the one electron wave function ($\psi$) in an atom.
3. C.The existence of Bohr's orbits is supported by hydrogen spectrum.
4. D.Atomic orbital is characterised by the quantum numbers $n$ and $l$ only.

Which of the following relation is not correct?

1. A.$\Delta \text{H}=\Delta \text{U}-\text{P}\Delta \text{V}$
2. B.$\Delta \text{U}=\text{q}+\text{W}$
3. C.$\Delta {\text{S}}_{\text{sys}}+\Delta {\text{S}}_{\text{surr}}\ge 0$
4. D.$\Delta \text{G}=\Delta \text{H}-\text{T}\Delta \text{S}$

In which of the following pairs, electron gain enthalpies of constituent elements are nearly the same or identical? (A) Rb and Cs (B) Na and K (C) Ar and Kr (D) I and At Choose the correct answer from the options given below :

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

Match List - I with List - II, match the gas evolved during each reaction. | | List - I | | List - II | |---|---|---|---| | (A) | $({\text{NH}}_4{)}_2{\text{Cr}}_2{\text{O}}_7\stackrel{\Delta }{\to }$ | (I) | ${\text{H}}_2$ | | (B) | ${\text{KMnO}}_4+\text{HCl}\to$ | (II) | ${\text{N}}_2$ | | (C) | $\text{Al}+\text{NaOH}+{\text{H}}_2\text{O}\to$ | (III) | ${\text{O}}_2$ | | (D) | ${\text{NaNO}}_3\stackrel{\Delta }{\to }$ | (IV) | ${\text{Cl}}_2$ | Choose the correct answer from the options given below :

1. A.(A) - (II), (B) - (III), (C) - (I), (D) - (IV)
2. B.(A) - (III), (B) - (I), (C) - (IV), (D) - (II)
3. C.(A) - (II), (B) - (IV), (C) - (I), (D) - (III)
4. D.(A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Which of the following has least tendency to liberate ${\text{H}}_2$ from mineral acids?

1. A.$\text{Cu}$
2. B.$\text{Mn}$
3. C.$\text{Ni}$
4. D.$\text{Zn}$

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

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

The metal salts formed during softening of hardwater using Clark's method are :

1. A.${\text{Ca(OH)}}_2$ and ${\text{Mg(OH)}}_2$
2. B.${\text{CaCO}}_3$ and ${\text{Mg(OH)}}_2$
3. C.${\text{Ca(OH)}}_2$ and ${\text{MgCO}}_3$
4. D.${\text{CaCO}}_3$ and ${\text{MgCO}}_3$

Which of the following statement is incorrect?

1. A.Low solubility of LiF in water is due to its small hydration enthalpy.
2. B.${\text{KO}}_2$ is paramagnetic.
3. C.Solution of sodium in liquid ammonia is conducting in nature.
4. D.Sodium metal has higher density than potassium metal.

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