List of top Chemistry Questions

The magnitude of the change in oxidising power of the MnO4− / Mn2+ couple is \( x \times 10^{-4} \) V, if the H+ concentration is decreased from 1 M to \( 10^{-4} \) M at 25 °C. (Assume concentration of MnO4− and Mn2+ to be same on change in H+ concentration). The value of \( x \) is __________ .
Copper reduces NO$_3^-$ into NO and NO$_2$ depending upon the concentration of HNO$_3$ in solution. (Assuming fixed [Cu$^{2+}$] and $P_{NO}=P_{NO_2}$), the HNO$_3$ concentration at which the thermodynamic tendency for reduction of NO$_3^-$ into NO and NO$_2$ by copper is same is $10^x$ M. The value of 2x is ________. (Rounded-off to the nearest integer)
[Given, E$^\circ_{Cu^{2+}/Cu}$=0.34 V, E$^\circ_{NO_3^-/NO}$=0.96 V, E$^\circ_{NO_3^-/NO_2}$=0.79 V and at 298 K, $\frac{RT}{F}$(2.303)=0.059]
For the reaction 2Fe$^{3+}$(aq) + 2I$^{-}$(aq) → 2Fe$^{2+}$(aq) + I₂(s) the magnitude of the standard molar free energy change, $\Delta_r G^o_m$ = - _________ kJ (Round off to the Nearest Integer). [Given : $E^o_{Fe^{2+}/Fe(s)}$ = -0.440 V; $E^o_{Fe^{3+}/Fe(s)}$ = -0.036 V $E^o_{I₂/2I^{-}}$ = 0.539 V; F = 96500 C]
These are physical properties of an element
(A) Sublimation enthalpy
(B) Ionisation enthalpy
(C) Hydration enthalpy
(D) Electron gain enthalpy
The total number of above properties that affect the reduction potential is _________. (Integer answer)
The conductivity of a weak acid HA of concentration 0.001 mol L$^{-1}$ is $2.0 \times 10^{-5}$ S cm$^{-1}$. If $\Lambda_m^\circ(HA) = 190$ S cm$^2$ mol$^{-1}$, the ionization constant (K$_a$) of HA is equal to _________ $\times 10^{-6}$. (Round off to the Nearest Integer)
The product obtained from the electrolytic oxidation of acidified sulphate solutions, is :

For water at 100$^\circ$C and 1 bar, 
(Round off to the Nearest Integer) 
[Use : R=8.31 J mol$^{-1}$ K$^{-1}$] 
[Assume volume of H$\_2$O(l) is much smaller than volume of H$\_2$O(g). Assume H$\_2$O(g) can be treated as an ideal gas] 
 

Data given for the following reaction is as follows: 
FeO(s) + C(graphite) \(\rightarrow\) Fe(s) + CO(g) 
The minimum temperature in K at which the reaction becomes spontaneous is _________. (Integer answer) 

 

For the reaction C₂H₆ → C₂H₄ + H₂ the reaction enthalpy ΔH = _________ kJ mol$^{-1}$. (Round off to the Nearest Integer). [Given : Bond enthalpies in kJ mol$^{-1}$ : C-C : 347, C=C : 611; C-H : 414, H-H : 436]
Five moles of an ideal gas at 293 K is expanded isothermally from an initial pressure of 2.1 MPa to 1.3 MPa against at constant external pressure 4.3 MPa. The heat transferred in this process is ________ kJ mol⁻¹. (Rounded-off to the nearest integer) [Use R=8.314 J mol⁻¹K⁻¹]
When 400 mL of 0.2 M H$_2$SO$_4$ solution is mixed with 600 mL of 0.1 M NaOH solution, the increase in temperature of the final solution is ________ $\times 10^{-2}$ K. (Round off to the Nearest Integer).
[Use : H$^+$(aq) + OH$^-$(aq) $\rightarrow$ H$_2$O(l) ; $\Delta_r H$ = -57.1 kJ mol$^{-1}$
Specific heat of H$_2$O = 4.18 J K$^{-1}$ g$^{-1}$
density of H$_2$O = 1.0 g cm$^{-3}$
Assume no change in volume of solution on mixing.]
The Born-Haber cycle for KCl is evaluated with the following data:
\(\Delta_f H^\ominus\) for KCl = -436.7 kJ \(mol^{-1}\); \(\Delta_{sub} H^\ominus\) for K = 89.2 kJ \(mol^{-1}\);
\(\Delta_{ionization} H^\ominus\) for K = 419.0 kJ \(mol^{-1}\); \(\Delta_{electron gain} H^\ominus\) for \(Cl_{(g)\) = -348.6 kJ \(mol^{-1}\);
\(\Delta_{bond} H^\ominus\) for \(Cl_2\) = 243.0 kJ \(mol^{-1}\).
The magnitude of lattice enthalpy of KCl in kJ \(mol^{-1}\) is _________. (Nearest integer)}
For the reaction $A_{(g)} \rightleftharpoons B_{(g)}$, the value of the equilibrium constant at 300 K and 1 atm is equal to 100.0. The value of $\Delta_r G^\circ$ for the reaction at 300 K and 1 atm in J mol$^{-1}$ is $-xR$, where $x$ is __________. (Rounded off to the nearest integer) [R=8.31 J mol$^{-1}K^{-1}$ and $\ln 10=2.3$]
At 298 K, the enthalpy of fusion of a solid (X) is 2.8 kJ \(mol^{-1}\) and the enthalpy of vaporisation of the liquid (X) is 98.2 kJ \(mol^{-1}\). The enthalpy of sublimation of the substance (X) in kJ \(mol^{-1}\) is ________. (in nearest integer)
200 mL of 0.2 M HCl is mixed with 300 mL of 0.1 M NaOH. The molar heat of neutralization of this reaction is \(-57.1\) kJ. The increase in temperature in \(^\circ C\) of the system on mixing is \(x \times 10^{-2}\). The value of \(x\) is _________. (Nearest integer)
[ Given : Specific heat of water \(= 4.18 \, \text{J g}^{-1} \text{K}^{-1}\)
Density of water \(= 1.00 \, \text{g cm}^{-3}\) ]
(Assume no volume change on mixing)
The incorrect expression among the following is :
Assuming ideal behaviour, the magnitude of log K for the following reaction at 25 °C is \( x \times 10^{-1} \). The value of \( x \) is __________ . (Integer answer) \( 3\,\text{HC}\equiv\text{CH (g)} \rightleftharpoons \text{C}_6\text{H}_6 \text{ (l)} \) [Given : \( \Delta_f G^\circ (\text{HC}\equiv\text{CH}) = -2.04 \times 10^5 \,\text{J mol}^{-1} \); \( \Delta_f G^\circ (\text{C}_6\text{H}_6) = -1.24 \times 10^5 \,\text{J mol}^{-1} \); \( R = 8.314 \,\text{J K}^{-1} \text{ mol}^{-1} \)]
The reaction of cyanamide, NH$_2$CN(s), with oxygen was run in a bomb calorimeter and $\Delta U$ was found to be -742.24 kJ mol$^{-1}$. The magnitude of $\Delta H_{298}$ for the reaction NH$_2$CN(s) + 3/2 O$_2$(g) $\rightarrow$ N$_2$(g) + CO$_2$(g) + H$_2$O(l) is _________ kJ.
For water \(\Delta_{vap}H=41\) kJ mol\(^{-1}\) at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is __________ kJ mol\(^{-1}\). (Nearest integer)
[Use: R=8.3 J mol\(^{-1}\)K\(^{-1}\)]
The bond order and magnetic behaviour of O\(_2^-\) ion are, respectively :
\(AB_3\) is an interhalogen T-shaped molecule. The number of lone pairs of electrons on A is _________. (Integer answer)

Match List - I with List - II : 

Choose the most appropriate answer from the options given below : 
 

The compound/s which will show significant intermolecular H-bonding is/are : 

 

The number of species having non-pyramidal shape among the following is _________.
(A) SO\(_3\)
(B) NO\(_3^-\)
(C) PCl\(_3\)
(D) CO\(_3^{2-}\)

The number of hydrogen bonded water molecule(s) associated with stoichiometry \( CuSO_4 \cdot 5H_2O \) is ____________