List of top Chemistry Questions

At equilibrium, the concentration of \( N_2 = 5 \times 10^{-3} \, \text{M} \), \( O_2 = 2.8 \times 10^{-3} \, \text{M} \), and \( NO = 1.4 \times 10^{-3} \, \text{M} \) in a sealed vessel at 800 K. What is the value of \( K_c \) for the reaction at the same temperature? \[ N_2(g) + O_2(g) \rightleftharpoons 2NO(g) \]
In a reaction, \( 3A \rightarrow \text{Products} \), the concentration of \( A \) decreases from 0.6 mol L\(^{-1}\) to 0.3 mol L\(^{-1}\) in 20 minutes. What is the rate of the reaction during this interval?
Given the reaction: \[ \text{Cu(s)} + 2\text{Ag}^+_{(aq)} \rightleftharpoons \text{Cu}^{2+}_{(aq)} + 2\text{Ag(s)} \quad (\text{E}_{\text{cell}}^\circ = 0.295 \, \text{V}, \, 2.303 \, \frac{RT}{F} = 0.059 \, \text{V}) \] What is the value of the equilibrium constant \( K \)?
Which of the following molecules has the highest standard enthalpy change of fusion (\( \Delta_{fus}H^\circ \)) (in kJ mol\(^{-1}\))?
Which of the following compounds is used to cover the surface of a metallic object to prevent corrosion?
Which of the following molecules has an expanded octet?
The increasing order of atomic radii is
Which of the following is correct about the stability of half-filled and completely filled subshells?
(i) Relatively small shielding
(ii) Larger coulombic repulsion energy
(iii) Smaller exchange energy
(iv) Smaller coulombic repulsion energy
(v) Larger exchange energy
Which of the following is an extensive property?
The correct order of ionization enthalpy is
Which of the following molecules has 3 bond pairs and 2 lone pairs of electrons?
A solution is prepared by adding 4 g of a substance to 46 g of ethanol. What is the mass percentage of the solute?
The order of energy of orbitals in the same subshell is
\( E^\circ_{\text{Cell}} = 1.1 \, \text{V}. \, \text{Find} \, E_{\text{Cell}} \, \text{for the reaction:} \, \text{Zn} + \text{Cu}^{2+} \, (0.1M) \rightleftharpoons \text{Zn}^{2+} \, (0.001M) + \text{Cu} \)
A first-order reaction is 75 percent completed in 6000s. What is the half-life?
Total number of orbitals when \( n = 3 \)?
Alkali metal with highest first ionization enthalpy is:
Molecule with 2\( \sigma \) and 2\( \pi \) bonds:
Number of valence electrons in Germanium?
Which of the following contains 2 primary –OH groups in its structure?
Maximum magnetic moment shown by:
Find the \( \Delta G \) during the reaction: \[ \text{H}_2\text{O}(l) \rightleftharpoons \text{H}_2\text{O}(g) \quad \Delta S = +1 \, \text{kJ/mol} \, \text{at} \, 100^\circ C \]
The most basic oxide
Given the following concentrations and rates, which one corresponds to the rate law for the reaction? \[ [A] = 0.10 \quad [D] = 0.2 \quad \text{Rate} = 0.2 \] \[ [A] = 0.2 \quad [D] = 0.2 \quad \text{Rate} = 0.4 \] \[ [A] = 0.10 \quad [D] = 0.1 \quad \text{Rate} = 0.05 \]
In which of the following \( K_c = K_p \)? a) \( \text{PCl}_5(g) \rightleftharpoons \text{PCl}_3(g) + \text{Cl}_2(g) \) b) \( \text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2\text{HI}(g) \)