Applied Chemistry
- An alloy of tin and lead contain 73% tin. Find the mass of eutectic in 1kg of solid Alloy, if the eutectic contains 64% of tin. Given: the alloy has 73% Sn (27% Pb), and the eutectic has 64% Sn (36% Pb). The alloy has more Sn (73%) than the eutectic (64%). On cooling,... 1
- 0.5 gm. of coal sample was burnt in Bomb calorimeter produced 0.06 gm. of BaSO4. calculate percentage of sulphur Given: mass of coal W = 0.5 g; mass of BaSO₄ = 0.06 g. Principle: S → SO₄²⁻ → BaSO₄. Since BaSO₄ = 233 and S = 32, 233 g of BaSO₄ contains 3... 1
- What is cathodic protection? How is it done by using impressed current and sacrificial anode? Explain with suitable examples. Cathodic protection: the metal to be protected is forced to act as the cathode of an electrochemical cell, so it does not corrode. Corrosion... 1
- Explain the effect of following factors on the rate of corrosion : (1) Nature of corrosion product. (2) pH (3) Anodic and cathodic areas (4) purity of metal (1) Nature of the corrosion product (oxide film): in dry corrosion the oxide layer formed on the surface decides further attack. Stable, non... 1
- Explain with neat suitable diagram determination of Carbon and hydrogen by ultimate analysis Principle: a known mass of coal is burnt completely in a current of dry, CO₂-free oxygen. Its carbon becomes CO₂ and its hydrogen becomes H₂... 1
- A sample of coal has the following composition C = 80 %, O = 8%, H = 6 %, S = 1.5%, N = 1 %, Calculate the higher and lower calorific values of coal. Given: C = 80%, H = 6%, O = 8%, S = 1.5%, N = 1% (N does not contribute to the heat). Dulong's formula (C, H, O, S in %): HCV = 1/100[8080 C... 1
- Write are the principles of Green Chemistry. The 12 principles of Green Chemistry (Anastas and Warner): Prevention: it is better to prevent waste than to treat or clean it up after it i... 1
- What do you mean by green solvent, explain it with suitable example. Green solvents are environmentally benign solvents that replace volatile, toxic and flammable organic solvents (benzene, CCl₄, CHCl₃). They... 1
- Explain synthesis of Indigo dye by traditional way and by green pathway. Traditional (conventional) synthesis – Heumann–Pfleger process: undersetanilineC₆H₅NH₂ + HCHO + HCN → C₆H₅NHCH₂CN xrightarrowhydrolysis unde... 1
- Define Matrix phase and dispersed phase with example. A composite has two constituents: 1. Matrix phase – the continuous phase that surrounds and binds the other phase. It may be a polymer, meta... 1
- Explain Laminar and sandwich panel of structural composite. Structural composites are made of homogeneous and composite layers. Their properties depend on the constituent materials and on the geometri... 1
- Explain a) Fiber glass reinforced composite. b) Carbon fiber reinforced composite. a) Glass-fibre reinforced composite (GFRP / fibreglass) Constituents: continuous or chopped glass fibres (E-glass, S-glass), about 3–20 µm i... 1
- Explain the term ‘glass transition temperature’ with significance. Glass transition temperature (T_g) is the temperature below which an amorphous polymer (or the amorphous part of a polymer) is hard, rigid a... 1
- A Polymer has the following composition: 100 Molecules of molecular mass 1000, 200 molecules of molecular mass 2000 and 500 molecules of molecular mass 5000. Calculate the number and weight average of molecular weight and the polydispersity index. (P… Given: N_iM_iN_iM_iN_iM_i² 10010001.0 × 10⁵1.0 × 10⁸ 20020004.0 × 10⁵8.0 × 10⁸ 500500025.0 × 10⁵125.0 × 10⁸ Σ = 80030.0 × 10⁵134.0 × 10⁸ Num... 1
- Explain following properties of polymer a) Electrical b) Optical. a) Electrical properties – most polymers are good insulators because they have no free electrons or ions. Dielectric strength: the maximum e... 1
- Give the purposes of making of an alloy. Alloys are made in order to: Increase hardness and strength. Pure metals are soft. Example: adding C to Fe gives steel; adding Cu to Au make... 1
- Define corrosion, how you will join the metals to prevent corrosion, justify with diagram. Corrosion is the gradual destruction or deterioration of a metal by chemical or electrochemical attack from its environment, starting at the... 1
- What are the characteristics of good fuel? A good fuel should: Have a high calorific value, so it gives more heat per unit mass. Have a moderate ignition temperature. If it is too low... 1