List of top Chemistry Questions

$\text{BF}_3$ reacts with $\text{NH}_3$ in 1:1 ratio and gives 'X'. The hybridization and geometry around B and N atoms in 'X' respectively are:

In H atom, electron is present in $n_x$ state. The angular momentum of this electron is $1.051 \times 10^{-34}\text{ Js}$. What is the energy (in J) required to excite this electron from $n_x$ state to $(n_x+1)$ state? ($h = 6.6 \times 10^{-34}\text{ Js}$; $\pi = 3.14$)

Consider the following oxides: $\text{SO}_2$, $\text{P}_2\text{O}_5$, $\text{SO}_3$, $\text{Al}_2\text{O}_3$, $\text{K}_2\text{O}$, MgO. The most acidic and most basic oxides are respectively:

The difference in bond angles between $\text{SO}_2$ and $\text{H}_2\text{O}$ is:

The element with atomic number 114 has outer shell electron configuration as that of element 'X'. What is X?

A gaseous mixture contains $\text{H}_2$ and $\text{O}_2$. The pressure of the mixture is $1\text{ bar}$. The weight percentage of $\text{O}_2$ is 80. The ratio of partial pressures of $\text{H}_2$ and $\text{O}_2$ is:

In hydrogen atom, electron is present in $n_x$ state. The energy of Lyman spectral line of hydrogen spectrum originated from $n_x$ state is $1.635 \times 10^{-18}\text{ J}$. What is the approximate energy (in J) required to excite this electron from $n_x$ state to $(n_x+1)$ state?

If the length of a linear antenna is increased by $60\%$ and the wavelength of the signal is decreased by $20\%$, then the percentage increase in the effective power radiated by the antenna is:

If A, B and C represent the power gain, base resistance and collector resistance respectively of a transistor connected in common emitter configuration, then the common emitter current amplification factor is:

The electron and hole concentrations in a semiconductor are $5 \times 10^{18}\text{ m}^{-3}$ and $8 \times 10^{19}\text{ m}^{-3}$ respectively. If the mobilities of the electron and hole are $0.24\text{ m}^2\text{V}^{-1}\text{s}^{-1}$ and $0.01\text{ m}^2\text{V}^{-1}\text{s}^{-1}$ respectively, then the conductivity of the semiconductor is:

If the radius of $_{13}\text{Al}^{27}$ nucleus is $3.6\text{ fm}$, then the number of neutrons in a nucleus of atomic number $29$ and radius $4.8\text{ fm}$ is:

What are C and E in the following reaction sequence?

Which of the following statements about \(C_6H_5N_2BF_4\) are correct? I. With NaF gives \(C_6H_5F\) II. With NaNO\(_2\)/Cu gives \(C_6H_5NO_2\) III. On heating gives \(C_6H_5F\) IV. With HNO\(_3\) gives \(C_6H_5NO_2\)

The detergent used in tooth pastes is 'X' and in hair conditioners is 'Y'. What are X and Y respectively?

Rate determining step in the following reactions I and II respectively is

Identify correct set(s) of X, Y, Z in the following reaction sequence. \[ Styrene \xrightarrow{(C_6H_5CO)_2O_2, HBr} Product \xrightarrow{(ii)X} \xrightarrow{(iii)Y} Z \]

What are X, Y, Z in the following reactions?

Glycosidic linkage in maltose is present between

Benzene gets converted to X in reaction (A) and Y in reaction (B). X is oxidized by ammoniacal AgNO\(_3\) but Y is not. Identify A and B.

Which of the following exhibit optical isomerism? I. \([Fe(C_2O_4)_3]^{3-}\) II. \([Cr(H_2O)_4Cl_2]^+\) III. \([Co(NH_3)_2(en)_2]^{3+}\)

Natural rubber is the addition polymer of monomer X and neoprene is the addition polymer of monomer Y. What are X and Y respectively?

In which of the following sets, the reaction and catalyst are correctly matched?

Match the following orders with their properties.

What are X and Y in the following reactions? \[ 2X_2(g)+2H_2O(l)\rightarrow4H^+(aq)+4X^-(aq)+O_2(g) \] \[ Y_2(g)+H_2O(l)\rightarrow HY(aq)+HOY(aq) \]

Observe the following reactions

Which are common for both Y and W? I. Four P-OH bonds II. Two P-H bonds III. Two \(P=O\) bonds IV. One P-O-P bond