Option “4” is correct. Nitrochloroform is used as anaesthetics before the operation of the patient to make them unconscious. Other options are explosive.
403. The Nucleus of Helium has-
1. Only one neutron
2. Two protons
3. Two protons and two neutrons
4. One proton and two neutrons
Option “3” is correct. Helium- (2He4) is a non-radioactive isotope of the element Helium. Its nucleus is identical to an alpha particle and consists of two protons and two neutrons.
Option “4” is correct. Solid camphor directly changes into camphor vapour and this process is called sublimation. The sublimation is the process in which some substances upon heating directly changes into vapour from and when cooled again directly turns into solid form.
406. Which one of the following is liquid at ordinary temperature?
1. Lead
2. Nickel
3. Mercury
4. Tin
Option “3” is correct. Mercury is the only common metal which is liquid at ordinary temperature.
407. Percentage of Silver in German Silver is:
1. 1%
2. 5%
3. 0%
4. None of these
Option “3” is correct. German Silver or Nickel silver is an alloy consisting 50% Copper, 35% Zinc and 15% Nickel. It doesn’t have silver.
408. In atom, neutron was discovered by:
1. J.J. Thomson
2. Chadwick
3. Rutherford
4. Newton
Option “2” is correct. Neutron is a neutral particle which has no electrical charge. It was discovered by Chadwick in 1932.
409. Change of water into the vapour is called-
1. Natural
2. Physical
3. Chemical
4. Biological
Option “2” is correct. Change of water into the vapour is called a physical change.
410. Which one of the following is the hardest metal?
1. Gold
2. Iron
3. Platinum
4. Silver
Option “3” is correct. Among non-metals, diamond is the hardest whereas, among the metals, platinum is the hardest.
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