2. at stp, how many liters of oxygen are required to react completely with 3.6 liters
of hydrogen to form water?
2h2(g) + o2(g)
2h20(g)

1.8 L.

Explanation:

2H₂(g) + O₂(g) → 2H₂O(g),

It is clear that 2.0 moles of H₂ react with 1.0 mole of O₂ to produce 2.0 moles of H₂O.

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

using cross multiplication:

1.0 mol of H₂ represents → 22.4 L.

??? mol of H₂ represents → 3.6 L.

∴ 3.6 L of H₂ represents = (1.0 mol)(3.6 L)/(22.4 L) = 0.1607 mol.

Using cross multiplication:

2.0 mol of H₂ react completely with → 1.0 mol of O₂, from stichiometry.

0.1607 mol of H₂ react completely with → ??? mol of O₂.

∴ The no. of moles of O₂ = (1.0 mol)(0.1607 mol)/(2.0 mol) = 0.08036 mol.

1.0 mol of O₂ represents → 22.4 L, at STP.

0.08036 mol of O₂ represents → ??? L.

∴ The no. of liters of O₂ will be produced = (0.08036 mol)(22.4 L)/(1.0 mol) = 1.8 L.

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.