The zinc within a copper-plated penny will dissolve in hydrochloric acid if the copper coating is filed down in several spots (so that the hydrochloric acid can get to the zinc). the reaction between the acid and the zinc is as follows: 2h+(aq)+zn(s)→h2(g)+zn2+(aq). when the zinc in a certain penny dissolves, the total volume of gas collected over water at 25 ∘c was 0.953 l at a total pressure of 752 mmhg .

0.0746 grams of hydrogen

Explanation:

To calculate the mass of hydrogen :

(Vapor pressure of water is 23.78 mmHg at 25 ∘C )

According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number of particles.

According to the ideal gas equation:

P = Total Pressure = 752 mm Hg

pressure of hydrogen = Total Pressure - Vapor pressure of water =  (752 -23.78 )mm Hg = 728.22 mm Hg =  0.958 atm   (760mmHg=1atm)

V= Volume of the gas = 0.953 L

T= Temperature of the gas = 25°C = 298 K  

R= Gas constant = 0.0821 atmL/K mol

n= moles of gas= ?

Mass of

Thus 0.0746 grams of hydrogen is collected.

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.