List of top Chemistry Questions

One of the reaction that takes place in producing steel from iron ore is the reduction of iron(II) oxide by carbon monoxide to give iron metal and CO₂.
\(FeO (s) + CO (g) ⇋ Fe (s) + CO_2 (g);\ K_p = 0.265\  \text {atm}\) at 1050 K
What are the equilibrium partial pressures of CO and CO₂ at 1050 K if the initial partial pressures are: \(P_{CO}\) = 1.4 atm and \(P_{CO_2}\) = 0.80 atm?

Describe the hybridisation in case of \( PCl_5\). Why are the axial bonds longer as compared to equatorial bonds?

The unpaired electrons in Al and Si are present in 3p orbital. Which electrons will experience more effective nuclear charge from the nucleus ?

Equilibrium constant, K_c for the reaction
\(N_2 (g) + 3H_2 (g) ⇋ 2NH_3 (g)\)
At 500 K is 0.061 At a particular time, the analysis shows that composition of the reaction mixture is 3.0 mol L^–1 N₂, 2.0 mol L^–1 H₂ and 0.5 mol L^–1 NH₃. Is the reaction at equilibrium? If not in which direction does the reaction tend to proceed to reach equilibrium?

Define hydrogen bond. Is it weaker or stronger than the van der Waals forces?

Indicate the number of unpaired electrons in : (a) P, (b) Si, (c) Cr, (d) Fe and (e) Kr.

(a) How many subshells are associated with n = 4 ? (b) How many electrons will be present in the subshells having ms value of \(-\frac{1}{2}\) for n = 4 ?

What is meant by the term bond order? Calculate the bond order of: \(N_2\), \(O_2\), \(O_2^+\) and \(O_2^-\) .

Bromine monochloride, BrCl decomposes into bromine and chlorine and reaches the equilibrium:
\(2BrCl (g) ⇋ Br_2 (g) + Cl_2 (g)\)
for which K_c = 32 at 500 K. If initially pure BrCl is present at a concentration of 3.3 × 10^–3 mol L^–1, what is its molar concentration in the mixture at equilibrium?

At 1127 K and 1 atm pressure, a gaseous mixture of CO and CO₂ in equilibrium with soild carbon has 90.55% CO by mass
\(C(s) + CO_2(g) ⇋ 2CO(g)\)
Calculate K_c for this reaction at the above temperature.

How do you account for the formation of ethane during chlorination of methane?

Calculate:

1. ∆G^Θ and 
2. the equilibrium constant for the formation of NO₂ from NO and O₂ at 298 K

\(NO (g) + \frac 12O_2 (g) ⇋ NO_2 (g)\)
where,
 ∆_fG^Θ (NO₂) = 52.0 kJ/mol
∆_fG^Θ (NO) = 87.0 kJ/mol
∆_fG^Θ (O₂) = 0 kJ/mol.

What are the necessary conditions for any system to be aromatic?

Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?

1. \(PCl_5 (g) ⇋ PCl_3 (g) + Cl_2 (g)\)
2. \(CaO (s) + CO_2 (g) ⇋ CaCO_3 (s)\)
3. \(3Fe (s) + 4H_2O (g) ⇋ Fe_3O_4 (s) + 4H_2 (g)\)

In the alkane \( H_3C-CH_2-C(CH_3)_2-CH_2-CH(CH_3)_2\) , identify 1°,2°,3° carbon atoms and give the number of H atoms bonded to each one of these.

What is meant by the conjugate acid-base pair? Find the conjugate acid/base for the following species: HNO₂, CN^– , HClO₄,F^–,OH^–,CO and S₂^–

What effect does branching of an alkane chain has on its boiling point?

Which of the following are Lewis acids? H₂O, BF₃, H⁺, and NH₄⁺.

Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.

1. \(COCl_2 (g) ⇋ CO (g) + Cl_2 (g)\)
2. \(CH_4 (g) + 2S_2 (g) ⇋ CS_2 (g) + 2H_2S (g)\)
3. \(CO_2 (g) + C (s) ⇋ 2CO (g)\)
4. \(2H_2 (g) + CO (g) ⇋ CH_3OH (g)\)
5. \(CaCO_3 (s) ⇋ CaO (s) + CO_2 (g)\)
6. \(4NH_3 (g) + 5O_2 (g) ⇋ 4NO (g) + 6H_2O(g)\)

Dihydrogen gas is obtained from natural gas by partial oxidation with steam as per following endothermic reaction:
\(CH_4 (g) + H_2O (g) ⇋ CO (g) + 3H_2 (g)\)

1. Write as expression for K_p for the above reaction.
2. How will the values of K_p and composition of equilibrium mixture be affected by
   1. increasing the pressure
   2. increasing the temperature
   3. using a catalyst?

Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.

Considering x-axis as the internuclear axis which out of the following will not form a sigma bond and why?

Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?

Name a suitable technique of separation of the components from a mixture of calcium sulphate and camphor.

Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam distillation ?