Solution:
DDT and BHC are hydrocarbons that may be carcinogenic. Laboratory animal studies showed effects on the liver and reproduction. DDT is considered a possible human carcinogen

Solution:
J.J. Thomson’s proposed model of atom is generally called plum and pudding model.

Solution:
Sulphur dioxide gas exhibits bleaching properties in presence of moisture. It dissolves in water liberating nascent hydrogen. Nascent hydrogen removes oxygen atoms from the colouring matter (reduces colouring matter) and it loses its colour.

Solution:
Natural pollution comes from natural sources like release of methane by cattle and paddy fields, carbon dioxide from plants and animals, dust storms, nitrogen oxides, ozone, volcanic eruptions, emission of natural gas, sol erosion, ultraviolet rays,etc. Mercury is not a cause of natural pollution.

Solution:
Hydrogen peroxide is used to restore the colour of old oil paintings containing lead oxide.

Solution:
A dry cell is a type of battery that uses a paste electrolyte, with only enough moisture to allow current to flow. It works in accordance with Faraday’s law of electrolysis. It consists of an outer case made of zinc (the negative electrode), a carbon rod in the center of the cell (the positive electrode), and the space between them is filled with an electrolyte paste. In operation the electrolyte, causes the electrons to flow and produce electricity.

Solution:
When the toxic effect of the mixture is greater than that expected for the sum of individual constituent doses, which is that effects of combined doses are more-than-additive, the interactions are said to be synergistic. Conversely, when the toxic effect of the mixture is less than that expected under the dose additivity assumption, the interactions are said to be antagonistic.