Your cart is empty.
Practice each question, then open the answer or worked solution.
In the preparation of H2SO4 by Contact Process, why is SO3 not absorbed directly in water to form H2SO4?
Dissolution of SO3 in water is highly exothermic. This leads to the formation of a mist of tiny droplets which are highly corrosive and they can even attack the lead pipelines (lead pipelines are used to cover the tower in contact process).
Write a balanced chemical equation for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.
NH3 + O2 →(Pt gauze) 4NO + 6H2O
Pt gauze reacts as a catalyst, which is added to increase the rate of reaction.
Write the structure of pyrophosphoric acid.
PH3 forms bubbles when passed slowly in water but NH3 dissolves. Explain why?
PH3 does not form hydrogen bonding with water. Therefore it is not soluble in water and it escapes as a gas and forms bubbles whereas ammonia forms hydrogen bonding and soluble in water.
In PCl5, phosphorus is in sp3d hybridised state but all its five bonds are not equivalent. Justify your answer with reason.
The size of axial bonds is greater than the size of equatorial bonds to overcome repulsion because the three equatorial bonds cause more repulsion. Therefore two axial P-Cl bonds are longer and different from equatorial bonds.
Why is nitric oxide paramagnetic in gaseous state but the solid obtained on cooling it is diamagnetic?
Nitric acid in the gaseous state exists in monomer form. It consists of only one unpaired electron therefore it is paramagnetic. In solid-state, it exists as a dimer (N2O2). There is no unpaired electron in its dimer form, therefore it is diamagnetic.
Give the reason to explain why ClF3 exists but FCl3 does not exist.
Chlorine has vacant d orbitals hence it can show an oxidation state of +3. Fluorine has no d orbitals, it cannot show a positive oxidation state. Fluorine shows only -1 oxidation state. Therefore FCl3 does not exists.
Out of H2O and H2S, which one has a higher bond angle and why?
H2O has higher bond angle than H2S because as we move from oxygen to sulphur the size of the central atom increases and electronegativity decreases due to which bond pair goes away from the central atom which results in a decrease in bond pair repulsion and hence bond angle decreases.
SF6 is known but SCl6 is not. Why?
Fluorine is the strongest oxidizing agent and it can oxidize sulphur to its maximum oxidation state +6 to form SF6. Chlorine is not a good oxidizing agent, it cannot oxidize sulphur to its maximum oxidation state. Chlorine can oxidize sulphur to only +4 oxidation state. Hence it can form SCl4 but not SCl6.
On reaction with Cl2, phosphorus forms two types of halides ‘A’ and ‘B’. Halide A is a yellowish-white powder but halide ‘B’ is a colourless oily liquid. Identify A and B and write the formulas of their hydrolysis products.
Halide A is PCl5 because it is a yellowish-white powder
Halide B is PCl3 because it is a colourless oily liquid.
PCl3 + 3H2O H3PO3 + 3HCl
PCl5 undergoes a violent hydrolysis
PCl5 + H2O POCl3 + 2HCl
PCl5 + 4H2O H3PO4 + 5HCl