A solution is prepared at that is initially in nitrous acid , a weak acid with , and in sodium nitrite . Calculate the pH of the solution. Round your answer to decimal places.

4.07

Explanation:

There is some info missing. I think this is the original question.

A solution is prepared at 25 °C that is initially 0.057 M in nitrous acid (HNO₂), a weak acid with Ka = 4.5 × 10⁻⁴, and 0.30 M in sodium nitrite (NaNO₂). Calculate the pH of the solution. Round your answer to 2 decimal places.

Nitrous acid is a weak acid and nitrite (coming from sodium nitrite) is its  conjugate base. Together, the form a buffer system. We can calculate its pH using the Henderson-Hasselbach equation.

pH = pKa + log [base]/[acid]

pH = -log 4.5 × 10⁻⁴ + log 0.30/0.057

pH = 4.07

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.