Not sure, is it <span>:
</span>B.
<span> 1.9 3 1027 NiCl2
formula units</span>
Answer:
Option (C)
Explanation:
The O horizon is the top layer of the soil, which occurs as both thick and thin soil at different places, and it is absent in certain places. It is comprised of organic matter which mainly includes the decomposed leaves and also sometimes, the dead remains of animals are also found which enhances the quality of the soil. This layer is also known as the humus or organic layer.
Thus, the correct answer is option (C).
Answer:
pH = 9.03
Explanation:
The equilibrium of the NH₄Cl / NH₃ buffer in water is:
NH₃ + H₂O ⇄ NH₄⁺ + OH⁻
Initial moles of both NH₃ and NH₄⁺ are:
0.100L ₓ (0.20 mol / L) = <em>0.0200 moles </em>
The NH₃ reacts with HCl producing NH₄⁺, thus:
NH₃ + HCl → NH₄⁺ + Cl⁻
<em>That means, moles of HCl added to the solution are the same moles are consumed of NH₃ and produced of NH₄⁺</em>
Moles added of HCl were:
0.025L ₓ (0.20mol / L) = 0.0050 moles of HCl. Thus, final moles of NH₃ and NH₄⁺ are:
NH₃: 0.0200 moles - 0.0050 moles = 0.0150 moles
NH₄⁺: 0.0200 moles + 0.0050 moles = 0.0250 moles.
Using H-H equation for bases:
pOH = pKb + log [NH₄⁺] / [NH₃]
<em>Where pKb is -log Kb =</em><em> 4.745</em><em>.</em>
Replacing:
pOH = 4.745 + log 0.0250mol / 0.0150mol
pOH = 4.967
As pH = 14- pOH
<em>pH = 9.03</em>
<em />
No of moles of HBr = 3.78g / 80.9 = 0.0467moles
Molarity = Number of moles/ volume. So we have 0.0467 / 4.5 = 0.0103M.
Kw = 1.0 x 10 -14 = [H3O+] [OH-] and [OH-] = 1.0 x 10^(-14) / [H3O+]
So [OH-] = 1.0 * 10^(-14) /1.03 *10^(-2) = 0.9703 * 10^(-12) M
