List of top Chemistry Questions

In the following system, $ PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g) $ at equilibrium, upon addition of xenon gas at constant T and p, the concentration of
The correct order of the complexes
[5pt] $[\text{Co(NH}_3)_5(\text{H}_2\text{O})]^{3+}$ (A),
[3pt] $[\text{Co(NH}_3)_6]^{3+}$ (B),
[3pt] $[\text{Co(CN)}_6]^{3-}$ (C),
[3pt] $[\text{CoCl(NH}_3)_5]^{2+}$ (D)
[5pt] in terms of wavelength of light absorbed is:
In the following reactions, which one is NOT correct?

Identify [A], [B], and [C], respectively in the following reaction sequence : 

Number of molecules from below which cannot give iodoform reaction is: Ethanol, Isopropyl alcohol, Bromoacetone, 2-Butanol, 2-Butanone, Butanal, 2-Pentanone, 3-Pentanone, Pentanal and 3-Pentanol

Which of the following properties will change when system containing solution 1 will become solution 2 ? 

Which of the following statements are correct? 
A. The process of the addition an electron to a neutral gaseous atom is always exothermic 
B. The process of removing an electron from an isolated gaseous atom is always endothermic 
C. The 1st ionization energy of the boron is less than that of the beryllium 
D. The electronegativity of C is 2.5 in $ CH_4 $ and $ CCl_4 $ 
E. Li is the most electropositive among elements of group 1 
Choose the correct answer from the options given below

Among $ 10^{-10} $ g (each) of the following elements, which one will have the highest number of atoms? 
Element : Pb, Po, Pr and Pt

Identify the correct statements from the following

Choose the correct answer from the options given below

Which of the following is the correct structure of L-fructose?
In a reaction A + B → C, initial concentrations of A and B are related as $ [\text{A}]_0 = 8[\text{B}]_0 $. The half lives of A and B are 10 min and 40 min, respectively. If they start to disappear at the same time, both following first order kinetics, after how much time will the concentration of both the reactants be same?

The metal ions that have the calculated spin only magnetic moment value of 4.9 B.M. are 
A. $ Cr^{2+} $ 
B. $ Fe^{2+} $ 
C. $ Fe^{3+} $ 
D. $ Co^{2+} $ 
E. $ Mn^{2+} $ 
Choose the correct answer from the options given below

Given below are two statements:
Statement I: A catalyst cannot alter the equilibrium constant ($ K_c $) of the reaction, temperature remaining constant.
Statement II: A homogeneous catalyst can change the equilibrium composition of a system, temperature remaining constant.
In the light of the above statements, choose the correct answer from the options given below.

Given below are two statements: 
Statement I : The N-N single bond is weaker and longer than that of P-P single bond 
Statement II : Compounds of group 15 elements in +3 oxidation states readily undergo disproportionation reactions. 
In the light of above statements, choose the correct answer from the options given below

Which of the following postulate of Bohr's model of hydrogen atom in not in agreement with quantum mechanical model of an atom ?
The percentage dissociation of a salt (MX$_3$) solution at a given temperature (van't Hoff factor $i = 2$) is .................. % (Nearest integer)
Thyroxine, the hormone has the given structure. The percentage of iodine in thyroxine is ............... % (nearest integer). (Given molar mass in g mol$^-$ C:12, H:1, O:16, N:14, I:127)
An organic compound weighing 500 mg, produced 220 mg of CO$_2$ on complete combustion. The percentage composition of carbon in the compound is ............... % (nearest integer).
(Given molar mass in g mol$^-$ of C: 12, O: 16)

The reactions which cannot be applied to prepare an alkene by elimination, are

Choose the correct answer from the options given below:

Given below are two statements: 
Statement I: D-(+)-glucose + D-(+)-fructose $\xrightarrow{H_2O}$ sucrose sucrose $\xrightarrow{\text{Hydrolysis}}$ D-(+)-glucose + D-(+)-fructose
Statement II: Invert sugar is formed during sucrose hydrolysis. 
In the light of the above statements, choose the correct answer from the options given below -

A person's wound was exposed to some bacteria and then bacteria growth started to happen at the same place. The wound was later treated with some antibacterial medicine and the rate of bacterial decay ($r$) was found to be proportional with the square of the existing number of bacteria at any instance. Which of the following set of graphs correctly represents the 'before' and 'after' situation of the application of the medicine?
[Given: $ N $ = No. of bacteria, $ t $ = time, bacterial growth follows 1st order kinetics.]
Which of the following compounds is least likely to give effervescence of CO$_2$ in presence of aq. NaHCO$_3$?
The first transition series metal 'M' has the highest enthalpy of atomisation in its series. One of its aquated ion (M$^{n+}$) exists in green colour. The nature of the oxide formed by the above M$^{n-}$ ion is:
The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ mol$^{-1}$ respectively. The above values are lowest among their group members. The nature of their ions A$^{2+}$ and B$^{4+}$ respectively is:
When a salt is treated with sodium hydroxide solution, it gives gas X. On passing gas X through reagent Y, a brown coloured precipitate is formed. X and Y respectively, are: