The reaction 2no(g) + o2(g) → 2no2(g) is a synthesis reaction. true false

True

Explanation:

Chemical reactions are broadly classified as:

1) Synthesis or combination reaction in which two or more substances react to form a single product

2) Decomposition reaction in which a complex substance breaks down into simpler molecules

3) Combustion reaction in which a substance like a hydrocarbon reacts with oxygen to form an carbon dioxide and water

4) Single displacement reaction in which a more reactive element replaces a less reactive element

5) Double displacement reaction which involves exchange of ions in solution

The given reaction is:

2NO + O2 → 2NO2

Here two substances combine to form a single molecule. This is an example of a synthesis reaction.

3

explanation:

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.