List of top Chemistry Questions

Which of the following coordination entities is expected to exhibit the maximum value of magnetic moment (spin-only)? \[ (\mathrm{Mn}=25,\ \mathrm{Fe}=26,\ \mathrm{Co}=27) \]

An antibiotic which is bactericidal in nature is:

Given below are two statements: Statement-I: The percent compositions of $\mathrm{Ni}^{2+}$ and $\mathrm{Ni}^{3+}$ in $\mathrm{Ni}_{0.98}\mathrm{O}$ respectively is 96% and 4%. Statement-II: The fraction of $\mathrm{Fe}^{3+}$ and $\mathrm{Fe}^{2+}$ ions in 1 mole of $\mathrm{Fe}_{0.93}\mathrm{O}$ is 0.14 and 0.79 respectively. Choose the correct option.

If the rate constant of a first-order reaction is $4.606\times10^{-3}\,\mathrm{s^{-1}}$, then the time taken (in seconds) for the concentration of the reactant to decrease from $1.0\,\mathrm{M}$ to $0.1\,\mathrm{M}$ is:}

Which alkanes undergo aromatization?

How many faradays of electricity are required to produce $12\,\mathrm{g}$ of magnesium from molten $\mathrm{MgCl_2}$?} \[ (\text{Atomic weight of Mg}=24\,\mathrm{g\,mol^{-1}}) \]

At $300\,\mathrm{K}$, a certain reaction has an equilibrium constant equal to 10. The value of $\Delta G^\circ$ for this reaction (in $\mathrm{kJ\,mol^{-1}}$) is:} \[ (R=8.314\,\mathrm{J\,K^{-1}mol^{-1}}) \]

A compound contains 69.4% C, 5.8% H, and the rest N and O. Nitrogen is estimated by Kjeldahl method. Find empirical formula.

Which compound is NOT isomeric with ethoxyethane?

The oxides of which element are responsible for photochemical smog?

Which of the following is NOT correctly matched with its common name?

Borax is Na$_2$B$_4$O$_7\cdot xH_2O$ and Kernite is Na$_2$B$_4$O$_7\cdot yH_2O$. Find (x − y).

1 mole of C$_5$H$_{10}$ on ozonolysis gives two compounds X and Y. Both give iodoform test. X gives Tollens' test but Y does not. Identify X and Y.}

Statement-I: CO reduces Al$_2$O$_3$ to Al.
Statement-II: CO is a neutral ligand with one $\sigma$ and two $\pi$ bonds.

The pair of elements which do NOT form superoxides in excess oxygen is:

Identify sets with only extensive or only intensive properties.

Identify the correct statements:
I. Hydrogen bonding is present in liquid water and ice.
II. Hydrogenation of vegetable oils produces vanaspati fat.
III. Water present in BaCl$_2\cdot2$H$_2$O is interstitial water.

A compound has 10.06% C, 0.84% H, 89.10% Cl. Find simplest ratio of C:H:Cl.

Buffer contains $[X^-]:[HX]=1:10$, and $K_b = 10^{-10}$. Find pH.}

10 L vessel contains He (0.4 g), O$_2$ (1.6 g), N$_2$ (1.4 g). Find partial pressure of He at 300 K.

Identify correct orders of covalent character:

Which of the following statements are NOT correct?
I. Addition of electron to a gaseous atom is always exothermic.
II. Removal of electron from gaseous atom is always endothermic.
III. First ionization enthalpy of oxygen is greater than nitrogen.
IV. In group I elements lithium is least electropositive.

Energy of orbit X of Li$^{2+}$ is $-2.18\times10^{-18}$ J. Find radius of same orbit (in Å).}

Match molecules with correct geometries:
BrF$_5$, XeF$_4$, ClF$_3$, SF$_4$

Identify correct orders with respect to properties:
I. B < Al < Mg < K (metallic character)
II. Si < P < C < N (electronegativity)
III. Si < C < N < F (non-metallic character)
IV. Al < Mg < S < P (ionization enthalpy)