B. A current in charges change direction
Explanation: an electric current that reverses its direction many times a second at regular intervals, typically used in power supplies.
Answer:
polymerization
Explanation:
Student is explaining the process of formation of a polymer and the process is called polymerization.
Polymer is made up of joining repeating units. The repeating units are called monomers.
Properties of the polymer is determined by the structure of monomer molecule.
For example, consider a well-known polymer Teflon.is made by the polymerization of tetrafluoroethane.
Thus, the student is explaining polymerization.
Answer:
Sulfur (Option-C) <span>exhibits chemical behavior similar to that of oxygen.
Explanation:
Sulfur has same chemical properties as that of Oxygen because both of them belongs to same group in the periodic table. Also, the similarity of chemical behaviour among the group members is due to same number of electrons in their valence shells.
For examole, the electronic configuration of Oxygen is,
1s</span>², 2s², 2p⁴
There are six valence electrons in the valence shell (i.e. 2) of Oxygen.
Now for Sulfur,
1s², 2s², 2p⁶, 3s², 3p⁴
There are six valence electrons in the valence shell (i.e. 3) of Sulfur.
Therefore, both elements tends to gain 2 electrons in a reaction and form O⁻² and S⁻² respectively.
Answer : The correct option is, (C) 6
Explanation :
Oxidation-reduction reaction : It is a reaction in which oxidation and reduction reaction occur simultaneously.
Oxidation reaction : It is the reaction in which a substance looses its electrons. In this oxidation state increases.
Reduction reaction : It is the reaction in which a substance gains electrons. In this oxidation state decreases.
The given unbalanced chemical reaction is,
Half reactions of oxidation and reduction are :
Oxidation : 
......(1)
Reduction : 
.......(2)
In order to balance the electrons, we multiply equation 1 by 2 and equation 2 by 3, we get:
Oxidation : 
......(1)
Reduction : 
.......(2)
The overall balanced chemical reaction will be:
From this reaction we conclude that the electrons are getting transferred from iron to iodine and the number of electrons transferred are 6 electrons.
Hence, the correct option is, (C) 6
Answer:
The new volume will be 42, 7 L.
Explanation:
We use the gas formula, which results from the combination of the Boyle, Charles and Gay-Lussac laws. According to which at a constant mass, temperature, pressure and volume vary, keeping constant PV / T. The conditions STP are: 1 atm of pressure and 273 K of temperature.
P1xV1/T1 =P2xV2/T2
1 atmx 22,4 L/273K = 0,5atmx V2/260K
V2=((1 atmx 22,4 L/273K )x 260K)/0,5 atm= 42, 67L
