Anyone know this? i will give to the one who helps me out.

Choose all 5 that are true about a catalyst.

Question 1 options:

You can use a graph to show how a catalyst lowers the activation energy.

A catalyst does change in a chemical reaction.

A catalyst does not change in a chemical reaction. It lowers the activation energy (like a short-cut).

The Nox, hydrocarbons and carbon monoxide in a car are examples because they are poisonous.

It raises the activation energy.

The gold and platinum in a car are examples because they help make the reactions happen to get rid of the poisons.

Enzymes such as lactase in your body are examples.

right

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.