Questions

Lime is sometimes applied to soil in order to increase the acidity of the soil.

Sunderbans is the name given to the dense impenetrable  tidal/ mangrove forest of Ganges-Brahmaputra delta because of abundant sundari trees found here.

In the thermite process, the reducing agent is Aluminium.

The alphabetical value of the letters in the left hand column follows through the sequence of Prime Numbers, with the letters in the right hand column representing the corresponding reverse alphabetical values. So,

M = Reverse of M = N.

In contrast to investment, consumption is relatively stable.

The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness".

Here in the given options, syrup has the highest viscosity.

Coal is chemically complex fuel. Whenever it is burned, gases are given off and particles of ash, called "fly ash," are released. Release of sulfur from burning into the air. The sulfur in coal combines with oxygen to form sulfur dioxide, which can be a major source of air pollution if emitted in large enough quantities. This stuff comes back as acid rain when it attaches itself to a raindrop. 

Today, many of the effects of coal burning have been reduced significantly or eliminated. This is super-nasty and is only stopped by buying low-sulfur coal from Montana or Wyoming. The eastern power plants have to pay to move the coal from out west and this increases the price of power production.