A. its high density
B. its high polishing
C. its chemical inertness
D. presence of free electrons
✅ The correct answer is option D.
Chemistry MCQs
The ionisation energy of hydrogen atom in the ground state is x KJ. The energy required for an electron to jump from 2nd orbit to 3rd orbit is
A. 5x/36
B. 5x
C. 7.2 x
D. x/6
✅ The correct answer is option A.
The mass number of a nucleus is
A. always less than its atomic number
B. the sum of the number of protons and neutrons present in the nucleus
C. always more than the atomic weight
D. a fraction
✅ The correct answer is option B.
The number of water molecules present in a drop of water (volume 0.0018 ml) at room temperature is
A. 1.568 x 103
B. 6.023 x 1019
C. 4.84 x 1017
D. 6.023 x 1023
✅ The correct answer is option B.
The main buffer system of the human blood is
A. H2CO3 – HCO3
B. H2CO3 – CO32-
C. CH3COOH – CH3COO-
D. NH2CONH2 – NH2CONH+
✅ The correct answer is option A.
The metal does not give H2 on treatment with dilute HCL is
A. Zn
B. Fe
C. Ag
D. Ca
✅ The correct answer is option C.
The first metal used by man was
A. iron
B. copper
C. gold
D. bronze
✅ The correct answer is option B.
The gas used for artificial ripening of green fruit is
A. ethylene
B. ethane
C. carbon dioxide
D. acetylene
✅ The correct answer is option A.
The ore which is found in abundance in India is
A. monazite
B. fluorspar
C. bauxite
D. magnetite
✅ The correct answer is option A.
The iron ore magnetite consists of
A. Fe2O3
B. Fe3OH4
C. FeCO3
D. 3Fe2O3 .. 3H2O
✅ The correct answer is option A.