General Science Chemistry MCQ
31. Which of the following metal has an ore named as ‘Cassiterite’?
[A] Bismuth
[B] Antimony
[C] Tin
[D] Uranium
[C] Tin
Notes:
Cassiterite is a tin oxide mineral. Its chemical formula is SnO2. It is the only commercially important source of tin. Cassiterite is generally opaque.
32. What do we call the process of converting an ore into its oxide by heating it in a limited supply of air below its melting point?
[A] Roasting
[B] Calcination
[C] Leaching
[D] Liquation
[B] Calcination
Notes:
Calcination is the process of converting an ore into its oxide by heating it in a limited supply of air or in absence of air, below its melting point. It is used to convert the concentrated ore to its oxide.
33. What is the probability of finding an electron at a point within an atom?
[A] Proportional to the square of the orbital wave function
[B] Proportional to the orbital wave function
[C] Proportional to the twice of the orbital wave function
[D] Proportional to the cube of the orbital wave function
[A] Proportional to the square of the orbital wave function
Notes:
The probability of finding an electron at a point within an atom is proportional to the square of the orbital wave function i.e., ψ|2 at that point. |ψ|2 is known as probability density and is always positive.
34. Which of the following orbital will be filled first among two orbitals?
[A] Orbital with higher value of (n+l)
[B] Orbital with lower value of (n+l)
[C] Orbital with lower value of (n)
[D] Orbital with lower value of (l)
[B] Orbital with lower value of (n+l)
Notes:
The rule for orbital filling states that the orbitals with lower value of (n+l) are filled first as they have lower energy.
35. Which of the following statements is correct about Beta-decay?
[A] In β+decay, Mass number increases by 2
[B] In β−decay, Mass number decreases by 2
[C] In β−decay, the atomic number increases by 1
[D] None of the above
[C] In β−decay, the atomic number increases by 1
Notes:
In both β− and β+ decay, the mass number A remains unchanged. In β− decay, the atomic number of the nucleus goes up by 1, while in β+ decay, the atomic number goes down by 1.
36. Which of the following represents the cell potential?
- [A] sum of the electrode potentials of the cathode and anode
[B] difference between the electrode potentials of the cathode and anode - [C] half of the sum of the electrode potentials of the cathode and anode
- [D] twice the difference between the electrode potentials of the cathode and anode
[B] difference between the electrode potentials of the cathode and anode
Notes:
The cell potential is the difference between the electrode potentials (reduction potentials) of the cathode and anode. It is measured in volts.
37. What is the Gibbs energy of a cell (nF=amount of charge passed, E= EMF of the cell)?
[A] -1/2nFE
[B] 2nFE
[C] -nFE
[D] nFE
[C] -nFE
Notes:
If the emf of the cell is E and nF is the amount of charge passed and ∆rG is the Gibbs energy of the reaction, then Gibbs energy is equal to – nFE.
38. Which of the following is / are correct statements about methane?
- The largest reservoir of methane on earth is under the permafrost at arctic and Antarctic
- Methane has a tetrahedral structure and also known as Hydrogen Carbide
- Methane can be produced by Serpentinite method
Select the correct option from codes given below:
[A] Only 1 & 2
[B] Only 1 & 3
[C] Only 2 & 3
[D] 1, 2 & 3
[C] Only 2 & 3
Notes:
Methane has a tetrahedral structure, which is multiplanar, in which carbon atom lies at the centre and the four hydrogen atoms lie at the four corners of a regular tetrahedron. The largest reservoir of methane on earth is under the seafloor. Serpentinite method is a method of producing Methane by inorganic method.
39. Which of the following monomers produce Buna-n polymer?
[A] Two parts of butadiene and styrene.
[B] Four parts of butadiene and one part of isobutylene.
[C] Two parts of butadiene and one part of acrylonitrile.
[D] None of the above
[C] Two parts of butadiene and one part of acrylonitrile.
Notes:
Buna-n polymer is obtained by copolymerization of two parts of butadiene and one part of acrylonitrile in presence of sodium metal.
40. Which one of these is not a linear polymer?
[A] Starch
[B] Polyethelene
[C] Nylons
[D] Polyesters
[A] Starch
Notes:
The polymers in which monomeric units are linked together to form linear chains are known as a linear polymer. Examples are polyethelene, nylons and polyesters.
