Introduction:
In the presence of sunlight, benzene reacts with chlorine gas (Cl2) to give a product, X. We are required to determine the number of hydrogens in the product X.

Explanation:
When benzene reacts with chlorine gas in the presence of sunlight, a substitution reaction known as electrophilic substitution occurs. The reaction proceeds as follows:

Step 1: Initiation
In the presence of sunlight, chlorine molecules (Cl2) are broken down into highly reactive chlorine atoms (Cl·) by homolytic cleavage, meaning each chlorine atom receives one of the shared electrons from the bond, thus forming two free radicals.

Step 2: Propagation
The chlorine radical (Cl·) attacks the benzene molecule, replacing one of the hydrogen atoms. This forms a benzene radical and a hydrogen chloride (HCl) molecule. The reaction is represented as:

C6H6 + Cl· -> C6H5· + HCl

Step 3: Termination
The benzene radical (C6H5·) reacts with another chlorine radical (Cl·) to form the final product X. This reaction is known as a radical substitution reaction. The reaction is represented as:

C6H5· + Cl· -> C6H5Cl

Product Analysis:
The product X formed is chlorobenzene (C6H5Cl), which is obtained by replacing one of the hydrogen atoms in benzene with a chlorine atom. Chlorobenzene consists of a benzene ring with a single chlorine atom attached to it.

Number of Hydrogens in X:
To determine the number of hydrogens in chlorobenzene (C6H5Cl), we need to count the number of hydrogen atoms.

In benzene, there are 6 hydrogen atoms. When one of the hydrogen atoms is replaced by a chlorine atom, the number of hydrogens decreases by 1.

Therefore, in the product X (chlorobenzene), there are 5 hydrogen atoms remaining.

However, we need to consider that the reaction mentioned in the question is carried out in the presence of sunlight. Under these conditions, multiple substitution reactions can occur, leading to the formation of different products. It is possible for multiple hydrogen atoms in benzene to be replaced by chlorine atoms.

In the case where all six hydrogen atoms in benzene are replaced by chlorine atoms, the product would be hexachlorobenzene (C6Cl6). In this compound, all the original hydrogens have been substituted by chlorine atoms.

Since the question does not provide any additional information about the specific conditions or the extent of the reaction, we cannot assume the complete substitution of all hydrogen atoms. Therefore, the correct answer is that the product X (chlorobenzene) contains 5 remaining hydrogen atoms.