question from OAT Practice Exam

[topdent1]

Chlorine bleaches are solutions that contain approximately 5% NaClO. These solutions are

A. slightly acidic.
B. strongly acidic.
C. neutral.
D. slightly basic.
E. strongly basic.


The answer is D. Care to explain why? I though ClO4 was a strong acid.

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[osimsDDS]

NaClO is a salt (conjugate base of a weak acid HClO)...Basically you started out like this:

HClO (hypochlorous acid) + NaOH -----> NaClO (conjugate base of a weak acid) + H20

The solution consists of HClO which is a weak acid and NaOH which is a strong base...weak acid + strong base = basic solution

Now to distinguish between D and E, slightly basic vs strongly basic I have no idea how you would be able to know that...maybe someone else can help

 

[Glycogen]

NaClO is a salt (conjugate base of a weak acid HClO)...Basically you started out like this:

HClO (hypochlorous acid) + NaOH -----> NaClO (conjugate base of a weak acid) + H20

The solution consists of HClO which is a weak acid and NaOH which is a strong base...weak acid + strong base = basic solution

Now to distinguish between D and E, slightly basic vs strongly basic I have no idea how you would be able to know that...maybe someone else can help

I chose d b/c as you mentioned it is a weak base,this (being weak base) and mentioning 5% will let us to conclude that it is slightly basic,I think.

 

[vvvv]

Chlorine bleaches are solutions that contain approximately 5% NaClO. These solutions are

A. slightly acidic.
B. strongly acidic.
C. neutral.
D. slightly basic.
E. strongly basic.


The answer is D. Care to explain why? I though ClO4 was a strong acid.

ClO- will hydrolyze water. ClO- + HOH = HClO + OH- this is slightly basic...

 

[shoombol tallah]

I think the OP is confusing ClO4(Perchlorate) with ClO(hypochlorite) . If the solution formed HCl04 instead of HClO then your right it would have been acid. When comparing oxyacids the more oxygens you have the strong the acid. For exampl HClO4>HClO3>HCl02>HClO. Hope that helps