| 1. State Faraday's first law of electrolysis. |
Faraday's First Law of Electrolysis states that the amount of substance deposited or liberated at an electrode during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte. Mathematically, it is expressed as m ∝ Q, where m is the mass of the substance and Q is the electric charge. |
| 2. What is vulcanization of rubber? |
Vulcanization of rubber is a chemical process that involves heating natural rubber with sulfur to improve its strength, elasticity, and durability. This process creates cross-links between polymer chains, making the rubber more resistant to heat, wear, and deformation. |
| 3. What are antiseptics? Give example. |
Antiseptics are substances that prevent the growth of microorganisms, such as bacteria, on living tissues, thereby reducing the risk of infection. An example is hydrogen peroxide, commonly used to clean wounds. |
| 4. What is blister copper? Why is it so-called? |
Blister copper is an impure form of copper, typically 96-99% pure, obtained during the smelting process of copper ores. It is so called due to its blistered surface, caused by sulfur dioxide gas escaping and forming bubbles as the molten copper cools. |
| 5. What are food preservatives? Give example. |
Food preservatives are substances added to food to prevent spoilage by inhibiting the growth of microorganisms or delaying chemical changes like oxidation. An example is sodium benzoate, commonly used in soft drinks and acidic foods. |
| 6. Aqueous Cu 2+ are blue in colour, whereas Aqueous Zn 2+ colourless. Why? |
Aqueous Cu 2+ ions are blue due to the d-d electron transitions in the partially filled d-orbitals of copper, absorbing light in the red-orange region. Aqueous Zn 2+ ions are colourless because zinc has a fully filled d-orbital (d 10 ), preventing such transitions. |
| 7. What is Ziegler-Natta catalyst? |
The Ziegler-Natta catalyst is a combination of a transition metal compound, typically titanium (like TiCl₄), and an organometallic compound, such as triethylaluminum, used to polymerize alkenes. It enables the controlled formation of polymers like polyethylene and polypropylene with specific structures. |
| 8. Ammonia is a good complexing agent - explain with an example. |
Ammonia (NH₃) is a good complexing agent because it can donate its lone pair of electrons to form coordinate bonds with metal ions, creating stable complexes. For example, it reacts with Cu²⁺ ions to form the deep blue [Cu(NH₃)₄]²⁺ complex in aqueous solution. |
| 9. Calculate the mole fraction of H 2 SO 4 in a solution containing 98% (w/w) H 2 SO 4 by mass. |
The mole fraction of H₂SO₄ is 1 / (1 + 0.111) ≈ 0.9. |
| 10. Write equations for the Carbylamine reaction of anyone aliphatic amine. |
The Carbylamine reaction of ethylamine (CH₃CH₂NH₂) with chloroform (CHCl₃) and potassium hydroxide (KOH) produces ethyl isocyanide: CH₃CH₂NH₂ + CHCl₃ + 3KOH → CH₃CH₂NC + 3KCl + 3H₂O. |
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