Option “A” is correct Nitrous oxide, commonly known as laughing gas or nitrous, is a chemical compound, an oxide of nitrogen with the formula N2O. At room temperature, it is a colorless non-flammable gas, with a slight metallic scent and taste.
102. Name two elements that find wide application in transistor industry.
1. Silicon and Germanium
2. Carbon and Platinum
3. Iridium and Germanium
4. Tungsten and Platinum
Option “A” is correct A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. Silicon and germanium are semiconductors which are widely used in transistors.
103. Which one of the following is known as the ‘brown coal’?
1. Anthracite
2. Bituminous
3. Coke
4. Lignite
Option “D” is correct Lignite, often referred to as brown coal, is a soft brown fuel with characteristics that put it somewhere between coal and peat. It is considered the lowest rank of coal due to its relatively low heat content. It has a carbon content around 60–70 percent.
104. In its reaction with silver nitrate, C2H2 shows-
1. oxidising property
2. reducing property
3. basic property
4. acidic property
Option “D” is correct Silver(I) nitrate react with acetylene to produce silver(I) acetylide and hydrogen chloride.
Option “D” is correct Hydrogen bomb is based on the principle of fusion reaction. It is uncontrolled reaction.
106. The technique of calculating the age of fossil organisms is –
1. Radiocarbon dating
2. Electroporation
3. Counting the annual rings
4. Micro Manipulation
Option “A” is correct The technique of calculating the age of fossil organisms is radiocarbon dating developed by Willard Libby and his colleagues in 1949.
107. The conversion of hard water into soft water by boiling or adding calcium hydroxide is called _______.
1. Baker’s process
2. Temp’s process
3. Clarke’s process
4. Lake’s process
Option “C” is correct Clark’s method is a process for the large-scale removal of temporary hardness from water. Clark’s process involves the addition of a controlled quantity of slaked lime .
108. Concentration of water vapour in troposphere is –
1. 04%
2. 10-14%
3. 20-24%
4. 30-34%
Option “A” is correct Water vapor is unique in that its concentration varies from 0-4% of the atmosphere depending on time of day.
109. First country to impose carbon tax is ________.
1. Australia
2. Iceland
3. USA
4. New Zealand
Option “D” is correct New Zealand is first country to impose carbon tax.
110. In the following reaction, fill in the blank.
Acid + Base → _______ + Water1. Carbon dioxide
2. Metal Oxide
3. Hydrogen Gas
4. Salt
Option “D” is correct When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt. The H(+) cation of the acid combines with the OH(-) anion of the base to form water.
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