Chemical Reactions and Processes

Deacon process is a method of preparation of chlorine by oxidation of hydrochloric acid.

During the electrolysis of aqueous solution of sodium chloride hydrogen gas is produced at the cathode, while chlorine gas is obtained at anode. There are two substances that can be reduced at the cathode: Na⁺ ions and water molecules. At cathode: Na⁺ + e^-  Â® Na       E^o_red = -2.71 V 2 H₂O + 2 e^- Â®H₂ + 2 OH^-                   E^o_red = -0.83 V It is much easier to reduce water than Na⁺ ions. Hence, the only product formed at the cathode is hydrogen gas. There are two substances that can be oxidized at the anode: Cl^- ions and water molecules. At anode:  2 Cl^- Â® Cl₂ + 2 e^-                        E^o_ox = -1.36 V 2 H₂O Â® O₂ + 4 H⁺ + 4 e^-                       E^o_ox = -1.23 V Due to closeness of the standard-state potentials for these half-reactions, we might expect a mixture of Cl₂ and O₂ gas collect at the anode. However, in practice only chlorine gas is obtained at anode.

Ziegler-Natta catalyst (titanium tetrachloride in the presence of triethylaluminium) is used in the polymerisation of ethene.

This statement is false about aluminium because aluminium liberates hydrogen from acid as well as bases. So, this option is correct.

Potassium chlorate is a compound containing potassium, chlorine, and oxygen, with the chemical formula KClO3. In pure form, it is a white crystalline substance. It is the most common chlorate in industrial use, and is usually present in well-stocked laboratories. It is used as an oxidizing agent to prepare oxygen as a disinfectant, in safety matches, and in explosives and fireworks. Potassium chlorate ( KCLO3 ) decomposes upon heating to yield potassium chloride and oxygen gas. Manganese dioxide ( MnO2 ) is mixed with potassium chlorate and behaves as a catalyst for this reaction . 2 KClO³ ---( Heat with MnO2 Catalyst )----> 2 KCl + 3 O^2_.

Acids give hydrogen gas along with a salt when they react with a metal. Here, a metal carbonate reacts with an acid to give carbon dioxide and water.

Magnesium and maganese are the metals,  which liberates hydrogen with dilute nitric acid.

 Hydrogen cannot be prepared by the action of hot 20% NaOH on silicon.

Oxygen bubbles will be formed on positive electrode and hydrogen bubbles will be formed on negative electrode.

Both Al and Be become passive in concentrated HNO3 because the acid forms a thin, protective oxide layer on their surface that prevents further reaction. This passivation is characteristic of metals that form amphoteric oxides and occurs only with concentrated nitric acid.

Ans : 2.

When alkali metals react with water, they produce hydrogen gas along with metal hydroxide. The general reaction is: 2M + 2H2O → 2MOH + H2. This is a characteristic property of alkali metals like sodium, potassium, and lithium.

Carbon dioxide can be prepared by the reaction of marble with sulphuric acid.

Heterogeneous catalysts act in a different phase than the reactants. Most heterogeneous catalysts are solids that act on substrates in a liquid or gaseous reaction mixture. For example, in the Haber process, finely divided iron serves as a catalyst for the synthesis of ammonia from nitrogen and hydrogen.

The Ostwald process is the industrial method for producing nitric acid from ammonia. It involves three steps: oxidation of ammonia to NO, oxidation of NO to NO2, and absorption of NO2 in water. The Haber process produces ammonia, Contact process produces sulfuric acid, and Lead chamber process is an older method for sulfuric acid production.