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Chemistry p1 doubt

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yasser37:
Hi guys

in June 10 paper 11
question 6
do I take the NH4 and No3 separately or as one unit when calculating?

also can someone explain questions 13 , 22 ,28 , abd 29

Deadly_king:

--- Quote from: yasser37 on November 17, 2010, 11:32:11 am ---Hi guys

in June 10 paper 11
question 6
do I take the NH4 and No3 separately or as one unit when calculating?

also can someone explain questions 13 , 22 ,28 , abd 29

--- End quote ---

Amonium nitrate exists as NH4+ and NO3-. So you should take each of the ions separately. ;)

Jun 10 p11

11. To maintain the concentration of HOCl high, you should impose a change which will cause the equilibrium to shift to the right so that more HOCl is formed at the expense of OCl-.

Adding a solution of Cl- or bubbling air through the water will have not effect on the equilibrium.

But adding a solution of OH-, will increase the latter's concentration. Hence according to La Chatelier's principle, the equilibrium will shift to the left which will in other words decrease concentration of HOCl.

Hence obvious answer is A.

The H+ from the acid will react with OH- to form water. Hence the concentration of OH- will decrease. In this way the equilibrium will shift to the right forming ore HOCl. ;)

I'll complete the rest asap. :)

yasser37:
Thanks m8 but I guess you answered a different question / paper

question 13 asks how does sulfuric acid act

Deadly_king:

--- Quote from: yasser37 on November 18, 2010, 07:15:33 am ---Thanks m8 but I guess you answered a different question / paper

question 13 asks how does sulfuric acid act

--- End quote ---

Oopz...........sorry dude, i did number 11 instead. ;D

13. Sulfuric acid reacts with sodium chloride to form sodium sulfate and hydrochloric acid. If you determine the oxidation numbers, you'll note that this is not a redox reaction.

Hence you can instantaneously eliminate B, C and D.

Therefore answer is A.

yasser37:
yes paper 11 question 13 says
How does conc. sulfuric acid act when added to NACL
acid
oxidizing agent
reducing agent
acid and oxidizing agent

also m8 if u can explain in w04 paper 1 Q 10 and 19

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