Question

When an excess of sodium hydroxide is added to an aqueous solution of ammonium chloride, gaseous ammonia is produced:

NaOH(aq) + NH4Cl(aq) → NaCl(aq) + NH3(g) + H2O(ℓ)

Suppose 3.68 g ammonium chloride reacts in this way at 30°C and a total pressure of 0.9884 atm. At this temperature, the vapor pressure of water is 0.0419 atm. Calculate the volume of ammonia saturated with water vapor that will be produced under these conditions, assuming no leaks or other losses of gas.

Answer 1

we know that p_Hg(partial pressure of Hg )=2.87*10^-6 atm= (1.01 * 10⁵)(2.87*10^-6) Pa=0.289 Pa

using ideal gas equation ,we have

pV=nRT

here,we have p=p_Hg,T=300K,R=8.31

putting all these in our equation ,

n/V=p/(R*T)   

n/V=0.289/(8.31*300)

=1.16*10^-4

   here , n/V=no. of moles per m³

   therefore, no. of mole per cm³=(n/v)/10^-6=1.16*10^-10=n₀

no. of Hg atoms per cm³=n₀*A₀   (A₀=Avogadro no.)

=(1.16*10^-10)(6.022*10²³)

=7.001*10¹³