The diagram shows the three steps of the fusion process in the sun.
in what order do the steps occur?
a. x, y, z
b. y, x, z
c. z, y, x
d. z, x, y

D. Z, X, Y

Explanation:

Step 1: Z

Within the Sun two protons fuse together and when this proton-proton pair breaks apart one proton transform into neutron due to weak nuclear force. Along with transformation of neutron, a positron also formed and proton-neutron pair sometimes form deuterium.

Step 2: X

Collision of third proton takes place with deuterium and this collision results in formation of Helium-3 along with gamma rays. These gamma rays are also released as sunlight.

Step 3: Y

Collision of two Helium-3 nuclei takes place which results in creation of Helium-4.

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.