Explanation:
the average atomic mass of chlorine= (34.968 x 0.7553) + ( 36.956 x 0.2447) = 35.4545
Ca % = 100x (5 x 40/502 ) = 39.84 % ( where 502 is molar mass of comp)
P% = 3 x 30.97367 x 100/502 = 18.51 %
O % = (100x13x16)/502 = 41.434
H % = 100-39.84-18.51-41.434 = 0.216 %
% Ca = 100 x40/( 116) = 34.483 %
% Si = 100 x28/116 = 24.14 %
% O = 100-34.483-24.14 = 41.38 %
How much
much hydrogen gas evolved
when 1.5 current is passed through water for 1.5 hours?
0.042 moles of Hydrogen evolved
Further explanationGiven
I = 1.5 A
t = 1.5 hr = 5400 s
Required
Number of Hydrogen evolved
Solution
Electrolysis of water ⇒ decomposition reaction of water into Oxygen and Hydrogen gas.
Cathode(reduction-negative pole) : 2H₂O(l)+2e⁻ ⇒ H₂(g)+2OH⁻(aq)
Anode(oxidation-positive pole) : 2H₂O(l)⇒O₂(g)+4H⁻(aq)+4e⁻
Total reaction : 2H₂O(l)⇒2H₂(g)+O₂(g)
So at the cathode H₂ gas is produced
Faraday : 1 mole of electrons (e⁻) contains a charge of 96,500 C
[tex]\tt mol~e^-=\dfrac{Q}{96500}[/tex]
Q = i.t
Q = 1.5 x 5400
Q = 8100 C
mol e⁻ = 8100 : 96500 = 0.084
From equation at cathode , mol ratio e⁻ : H₂ = 2 : 1, so mol H₂ = 0.042
