Question

Hydrogen cyanide is prepared commercially by the reaction of methane, CH4(g), ammonia, NH3(g), and oxygen, O2(g), at high temperature. The other product is gaseous water.

(a) Write the chemical equation for the reaction. (Use the lowest possible coefficients.)

_CH4(g) + _NH3(g) + ____(g) + ____(g) + _H2O(g)

(b) What volume (in liters) of HCN(g) can be obtained from 50.0 L CH4(g), 50.0 L NH3(g), and 50.0 L O2(g)? The volumes of all gases are measured at the same temperature and pressure.

Answer 1

a)

the balanced chemical equation is given by

1 CH4 (g) + 1 NH3 (g) + (3/2) 02 (g) ----> 1 HCN (g) + 3 H20 (g)

b)

we know that

according to ideal gas equation

PV = nRT

all the conditions are same for all the gases

so

moles and volume are proportional

noow

given equal volumes of CH4 , NH3 and O2

so

number of moles of CH4 , NH3 and 02 are same

now

from the reaction

we can see that

moles of O2 required = 1.5 x moles of CH4 = 1.5 x moles of NH3

but

equal moles of 02 , CH4 and NH3 are present

so

02 is the limiting reagent

now

from the reaction

we can see that

moles of HCN formed = (2/3) x moles of 02

as PV = nRT ,

volume of HCN formed = ( 2/3) x 50

volume of HCN formed = 33.33 L

so

33.33 L of HCN is formed