List of top Chemistry Questions

According to molecular orbital theory, the number of unpaired electron(s) in $\text{O}_2^{2-}$ is ________.
Which among the following species has unequal bond lengths?
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Lithium halides are some what covalent in nature.
Reason R : Lithium possess high polarisation capability.
In the light of the above statements, choose the most appropriate answer from the options given below :
The difference between bond orders of CO and NO$^\oplus$ is $\frac{x}{2}$ where x = _________. (Round off to the Nearest Integer)
In gaseous triethyl amine the "-C-N-C-" bond angle is _________ degree.
According to molecular orbital theory, the species among the following that does not exist is :
The ionization enthalpy of Na$^+$ formation is 495.8, electron gain enthalpy of Br is -325.0, and lattice enthalpy of NaBr is -728.4 kJ mol$^{-1}$. The energy for the formation of NaBr ionic solid is (-) __________ $\times 10^{-1}$ kJ mol$^{-1}$.
Which of the following are isostructural pairs ? (Note: Based on typical JEE pairs like $SO_4^{2-}$ and $BF_4^-$ or $NH_3$ and $PH_3$)
The number of species below that have two lone pairs of electrons in their central atom is _________. (Round off to the Nearest Integer). SF₄, BF₄⁻, ClF₃, AsF₃, PCl₅, BrF₅, XeF₄, SF₆
The total number of electrons in all bonding molecular orbitals of O$_2^{2-}$ is ________.
(Round off to the Nearest Integer).
The number of sigma bonds in \(H_3C-CH=CH-C\equiv CH\) is ________.
AX is a covalent diatomic molecule where A and X are second row elements of periodic table. Based on Molecular orbital theory, the bond order of AX is 2.5. The total number of electrons in AX is _________. (Round off to the Nearest Integer).
The correct shape and I-I-I bond angles respectively in $I_3^-$ ion are :
The correct set from the following in which both pairs are in correct order of melting point is :
83 g of ethylene glycol dissolved in 625 g of water. The freezing point of the solution is ___________ K. (Nearest integer)
Use: Molal Freezing point depression constant of water = 1.86 K kg mol\(^{-1}\)
Freezing point of water = 273 K
Atomic masses: C: 12.0 u, O: 16.0 u, H: 1.0 u
An aqueous KCl solution of density 1.20 g \(mL^{-1}\) has a molality of 3.30 mol \(kg^{-1}\). The molarity of the solution in mol \(L^{-1}\) is _________. (Nearest integer)
[Molar mass of KCl = 74.5]
Of the following four aqueous solutions, total number of those solutions whose freezing point is lower than that of 0.10 M \(C_2H_5OH\) is _________. (Integer answer)
(i) 0.10 M \(Ba_3(PO_4)_2\)
(ii) 0.10 M \(Na_2SO_4\)
(iii) 0.10 M KCl
(iv) 0.10 M \(Li_3PO_4\)
1 kg of 0.75 molal aqueous solution of sucrose can be cooled up to \(-4^\circ C\) before freezing. The amount of ice (in g) that will be separated out is _________. (Nearest integer)
[ Given : \(K_f(H_2O) = 1.86 \, \text{K kg mol}^{-1}\) ]
40 g of glucose (Molar mass = 180) is mixed with 200 mL of water. The freezing point of solution is _________ K. (Nearest integer)
[Given: K\(_f\)= 1.86 K kg mol\(^{-1}\); Density of water=1.00 g cm\(^{-3}\); Freezing point of water = 273.15 K]
Which one of the following \( 0.10 \, \text{M} \) aqueous solutions will exhibit the largest freezing point depression ?
Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is ________ $\times 10^{-1}$ M. (Nearest integer) [Atomic mass : Na = 23.0, O = 16.0, H = 1.0]
If a compound AB dissociates to the extent of 75% in an aqueous solution, the molality of the solution which shows a 2.5 K rise in the boiling point of the solution is ________ molal. (Rounded-off to the nearest integer) [K$_b$=0.52 K kg mol⁻¹]
The density of NaOH solution is 1.2 g cm$^{-3}$. The molality of this solution is ________ m. (Round off to the Nearest Integer)
[Use : Atomic masses : Na:23.0 u O:16.0 u H:1.0 u, Density of H$_2$O : 1.0 g cm$^{-3}$]
1.46 g of a biopolymer dissolved in a 100 mL water at 300 K exerted an osmotic pressure of $2.42 \times 10^{-3}$ bar. The molar mass of the biopolymer is _________ $\times 10^4$ g mol$^{-1}$. (Round off to the Nearest Integer)
[Use : R = 0.083 L bar mol$^{-1}$ K$^{-1}$]
1 molal aqueous solution of an electrolyte A$_3$B$_3$ is 60% ionised. The boiling point of the solution at 1 atm is __________ K. [Given $K_b$ (H$_2$O) = 0.52 K kg mol$^{-1}$, $T_b$ pure water = 373.15 K]