4321. Which of the following metal does not undergo corrosion due to the formation of oxide layer -
| Answer : Option B |
| Explanation : |
| Aluminium.Corrosion is an oxidation reaction with atmospheric oxygen in the presence of water on the surface of a metal. Aluminium also undergoes an oxidation reaction, but does not oxidize & corrode as quickly as its reactivity suggests. Iron corrodes more quickly than most other transition metals to form an iron oxide. Once a thin oxide layer of Al2O3 has formed on the surface, it forms a barrier to oxygen & water to prevent further corrosion of the aluminium. |
4323. Which quantum number cannot have an integral value?
| Answer : Option A |
| Explanation : |
4324. The ratio of pure gold in 18 carat gold is:
| Answer : Option A |
| Explanation : |
| 75%.There are various grades of gold purity, determined by the ratio of their alloy composition & rated by a karat system. 18 karat gold consists of 75% gold & 25% alloy metals. Typical karat purities range from 10 karats to 24 karats (pure gold), with a wide variation of usage from country to country. 18 karat gold has been found to be the perfect balance between gold purity & strength. Brilliance offers a variety of exquisite 18 karat gold jewelry. |
4325. Denaturation of a protein is caused by
| Answer : Option D |
| Explanation : |
4326. The radiation initially produced in fluorescent tube is
| Answer : Option B |
| Explanation : |
| ultraviolet.The primary radiation that is initially produced within a fluorescent lamp is analogous to that emitted by a low pressure mercury lamp. A phosphorescent coating on the inside of the tubes absorbs the UV & converts it to visible light. Fluorescent lamps produce UV radiation by ionizing low-pressure mercury vapour. |
4327. Coating of solid waste with impervious material is known as
| Answer : Option C |
| Explanation : |
| Encapsulation.Containment of toxic or hazardous constituents in industrial solid wastes is currently being accomplished using: (i) coating grains of waste material with an inert & non-reactive impervious material (microencapsulation), & (ii) coating blocks of waste material with an inert, non-reactive impervious material (macroencapsulation). |
4328. The common name of sodium bicarbonate is
| Answer : Option D |
| Explanation : |
| Baking soda.Sodium bicarbonate (NaHCO3) is also known as baking soda, bread soda, cooking soda, & bicarbonate of soda. It reacts with acidic components in batters, releasing carbon dioxide, which causes expansion of the batter & forms the characteristic texture & grain in pancakes, cakes, quick breads, etc. It is primarily used in cooking (baking), as a leavening agent. |
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