Achieve week 2 question 7
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Achieve week 2 question 7
Hi for this question it gave the Ka for HClO and we had to find the pH for NaClO, but can someone please explain why we had to find it as a base using Kb? Is it because ClO is the conjugate base for HClO?
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Re: Achieve week 2 question 7
HI Chelsea! Because they gave us a weak acid and its conjugate salt we know it is going to be a base, so we need the Kb. In this case, if we look at NaClO, we can see that it will dissociate, into Na+ and ClO-, this ClO- will then combine with water to form HClO and OH-, so it is a basic solution. Therefore, you would need to convert the Ka into the Kb, using the formula Ka x Kb= 1.00 x 10^-14.
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Re: Achieve week 2 question 7
Hello,
Given NaClO as the reactant, we know that Na+ is a spectator ion and does not affect the pH, so we can take it out of the compound to get ClO- in our chemical reaction instead: ClO- + H2O(l) <--> HClO + OH-.
We are given the Ka value for HClO, but since HClO is the conjugate acid of ClO- and ClO- is the one being reacted with H2O, we need to find the Kb value instead by using Kw=Ka x Kb.
Given NaClO as the reactant, we know that Na+ is a spectator ion and does not affect the pH, so we can take it out of the compound to get ClO- in our chemical reaction instead: ClO- + H2O(l) <--> HClO + OH-.
We are given the Ka value for HClO, but since HClO is the conjugate acid of ClO- and ClO- is the one being reacted with H2O, we need to find the Kb value instead by using Kw=Ka x Kb.
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