Chemical Reactions and Processes

Sodium, potassium, and lithium are all alkali metals (Group 1) that react vigorously with water to produce hydrogen gas and their respective hydroxides. Cadmium is a transition metal that does not react with water under normal conditions, making it the correct answer.

In a hydrogen fuel cell, hydrogen and oxygen combine to form water (H2O) as the primary product. Electrons flow through the external circuit creating electrical current, which is the useful output. Early spacecraft used fuel cells to provide both electricity and drinking water for astronauts. Neutrons and neutrinos are not produced in this reaction.

Sulfuric acid is manufactured by the Contact process, which involves catalytic oxidation of SO2 to SO3 over vanadium pentoxide catalyst, followed by absorption in concentrated H2SO4 to form oleum. The name 'Contact' refers to the solid catalyst that 'contacts' the reacting gases. The other options (explosive, emission, fission, chain) are not related to H2SO4 manufacturing.

Metallic potassium (option B) is highly reactive with water and ignites spontaneously upon contact, producing hydrogen gas and heat. The reaction is 2K + 2H2O → 2KOH + H2 + heat. Granulated magnesium (A) doesn't ignite in water at room temperature, 'Ethiline' (C) appears to be a typo for ethylene or a similar compound, and ethanol (D) is miscible with water without ignition.

When dilute sulphuric acid reacts with zinc metal, hydrogen gas is evolved. This is a classic single displacement reaction producing zinc sulfate and hydrogen gas. Hydrogen peroxide (H2O2) is not produced, argon is inert, and sulfur dioxide would require different reactants/conditions.

When an acid reacts with an alkali (base), a neutralization reaction occurs producing salt and water. For example, HCl + NaOH gives NaCl (salt) + H2O (water). Option A describes the reaction name, not the products. Hydrogen gas is produced when acids react with metals, not alkalis.

Pearl formation is triggered when irritant particles (such as parasites, debris, or implanted beads in cultured pearls) enter the mollusk's shell. The mollusk secretes nacre (mother-of-pearl) to coat the irritant, layer by layer, creating the pearl. Pheromones are chemical signals between organisms, not related to pearl formation. Water chemistry changes don't directly trigger pearl formation - it's the physical irritant that matters.

Sodium bicarbonate (NaHCO3) reacts rapidly with dilute sulfuric acid to produce carbon dioxide gas through acid-base reaction: 2NaHCO3 + H2SO4 → Na2SO4 + 2H2O + 2CO2. This quick CO2 generation makes it ideal for fire extinguishers. Marble, magnesite, and limestone react too slowly for effective emergency use.

Correct answer. H₃Ru₃NiCp(CO)₉ clusters contain Ru-Ni as core metals, which catalyse the azane synthesis.

Correct answer. Hydrazine (N₂H₄) is a nitrogen hydride. In Raschig process, it is prepared by the reaction of ammonia with sodium hypochlorite in a dilute aqueous solution and Boric acid is a weak monobasic acid. It is not a protonic acid, but acts as a Lewis acid by accepting an electron pair from a hydroxyl ion. Hence, statements 1 and 3 are false.  

KMnO4 reacts with di HCl and gives chlorine gas. 2KMnO₄ + 16 HCl ------>2KCl + 2MnCl₂ + 5Cl₂ +2H₂O                 

It turns blue litmus into red which finally bleaches to white.

Conc. H₂SO₄  is used as a drying agent for Hydrogen chloride gas because it does not react with HCl.

Hydrogen gas is evolved when dil HCl is added to Magnesium. Mg + 2HCl ---> MgCl₂ + H₂

Hydrogen sulphide gas is liberated on reacting Iron(II) Sulphide with dilute HCl.