1. Copper and Zinc
2. Copper and Tin
3. Zinc and Nickel
4. Aluminium and Nickel
Option “B” is correct Bronze Alloy is an alloy composed of copper and tin.
22. Which of the following causes fly ash?
1. Hydroelectric Power Station
2. Coal Combustion Power Plant
3. Nuclear Power Plant
4. Tidal Power Plant
Option “B” is correct Fly ash is a byproduct from burning pulverized coal in electric power generating plants. During combustion, mineral impurities in the coal (clay, feldspar, quartz, and shale) fuse in suspension and float out of the combustion chamber with the exhaust gases. As the fused material rises, it cools and solidifies into spherical glassy particles called fly ash.
Option “A” is correct Sulphuric acid is known as oil of vitriol, because it is dense, colour less, oily corrosive liquid most commonly known as hydrogen sulfate. Sulfuric acid is called “oil of vitriol” because in older times it was prepared from green vitriol
24. The melting point of ice is ____ K.
1. 253.16
2. 263.16
3. 273.16
4. 283.16
Option “C” is correct The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. The melting point of ice is 273.16 K.
Option “C” is correct A fire extinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations. They contain pure carbon dioxide which is a clean extinguishant, leaving no residue. Suitable for flammable liquid fires (petrol, oil, solvents), and recommended for use on live electrical equipment.
26. Which one of the following has the highest fuel value?
1. Hydrogen
2. Charcoal
3. Natural gas
4. Gasoline
Option “A” is correct The heating value of a fuel is the amount of heat that is obtained after one gram (1gm) of fuel is burnt completely in air or oxygen. Hydrogen has the highest heating value among all fuels. Hydrogen is used as a rocket fuel and in burner producing high temperature.
27. The main component of Liquid Petroleum Gas (LPG) are:
1. Methane, Ethane and Hexane
2. Methane, Pentane and Hexane
3. Propane and Butane
4. Methane, Carbon Monoxide and Hydrogen
Option “C” is correct LPG is the abbreviation or short form Liquefied Petroleum Gas. Like all fossil fuels, it is a non-renewable source of energy. It is extracted from crude oil and natural gas. The normal components of LPG thus are propane (C_3 H_8 ) and butane (C_4 H_10 ).
28. The pH-value for water is-
1. Nearly zero
2. Nearly 7
3. 5 or less than 5
4. 8.7 or more
Option “B” is correct The pH value of pure water is 7. Pure water is neutral by nature. The solution with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline.
29. The gas used in the manufacture of Vanaspati Ghee from Vanaspati Oil is-
Option “A” is correct Hydrogen gas is used in the manufacturing of Vanaspati ghee. To prepare the Vanaspati ghee, hydrogen gas is passed through vegetable oils under 8-10 atmospheric pressure in the presence of nickel powder at a temperature of 200°C, oil changes into vegetable ghee or solid fat known as Vanaspati ghee.
30. Which one of the following is also called Stranger Gas?
1. Argon
2. Neon
3. Xenon
4. Nitrous Oxide
Option “C” is correct Xenon is a chemical gas with symbol Xe and atomic number 54. It is a rare, odourless, colourless, tasteless, chemically unreactive gas. Xenon gas is also known as stranger gas as its volume is low in the atmosphere.
Q. 1. Ribosomes are made up of..
1. Protein and RNA
2. Protein and DNA
3. Carbohydrates
4. Cellulose
Q. 2. Electron transport chain occur at …
1. Protein fibre
2. Cellulose
3. mitochondrial inner membrane
4. Callose
banothshailu@123gemil.come
Which instrument is used to capture the purity of milk?
(A) hydrometer
(B). Isometric
(C). Lacto meter
Lactometer
I Love chemical…it’s my favourite subject..mere iss mein se hmesha hi boht ache marks aate hai….and my interest is also in chemistry…
Protein and RNA
Protein and RNA
vvvwvrww
Very good
Question bank chapter wise for class 12th CBSE 2025 board examination PCB