Chemistry: Post your doubts here!

[princess Anu]

Of course D should be answer coz PH 6 is acid but weak acid and they undergo dissociation but not fully.
Student P is wrong coz PH 6 is not the value for strong acids ( it should be PH 1-3)
Got?

but why is Q correct

 

[♣♠ Magnanimous ♣♠]

but why is Q correct

Coz PH 6 are weak acids and they dont undergo complete dissociation whereas strong acids fully dissociates when dissolved in water.

 

[princess Anu]

3 is answer coz here are possiblilities --->
1)CH3-CH3
2)CH3-Cl
3)C2H5-C2H5

I hope you got it

I am unsure a bit RoOkaYya G [/USER] help me.

But i think these should be the forms :/

 

[♣♠ Magnanimous ♣♠]

But i think these should be the forms :/

Oh shit! I messed up
You are correct

 

[asadalam]

but why is Q correct

Neutral Ph is 7,q said the extent of dissociation in Y is higher as it changes the value of water by 2 whereas acid changes by -1 unit,hence q is right.

 

[Al. Ahmad]

june 2011 paper 41 question 8 (b) part..
it is related to two way chromatography..
can anyone pleaaaase help?

 

[immie.rose]

june 2011 paper 41 question 8 (b) part..
it is related to two way chromatography..
can anyone pleaaaase help?

take it this way: Solvent 1 is responsible for separating the 'dots' height-wise. And Solvent 2, length-wise.
for b(i) you can see the 'dot' marked with red circle is the answer. this 'dot' couldn't go up height-wise, because it is insoluble in solvent 1. but it moved towards right due to its solubility in solvent 2.
for b(ii) you would notice two dots are at the same height. This suggests that although they gained height due to their solubility in solvent 1, they got separated only due to solvent 2, as one of the 'dots' moved further to the right than the other.
Hence, these two dots should be marked as A and B.
Hope that helps.

 

[Muskan Achhpilia]

Hey please can someone help me out with all these questions?I have also added the marking scheme.


Thanks a lot!

 

[irtixahaider]

can somebody please upload all the end of chapter answers to the coursebook by roger norris?

 

[princess Anu]

 

[princess Anu]

Can someone please solve these..
They are from Electrochemistry & Kinetics

 

[princess Anu]

pleaseeee

 

[The Chill Master]

View attachment 51093 pleaseeee

As far as i think they are asking for temperature change means your solution was at 6 degrees Celsius and it had 50cm^3 solution you added another 50 what will be your temperature change.Thermometer reading will be 6 degrees Celsius but since they are asking for temperature change 12-6.

 

[Metanoia]

View attachment 51093 pleaseeee

Temperature increase (due to heat of neutralization) should still be 6 degree celsius.

Expt 1: 50cm3 of acid + 50 cm3 of alkali (0.05 mol of water formed, releasing heat)
Expt 2: 100cm3 of acid + 100 cm3 of alkali (0.1 mol of water formed, releasing heat)

Basically you are generating 2 twice the amount of heat in expt 2, but its used to heat up twice the volume of solution. So temperature rise is the same in both experiments.

More importantly in this question, mixing any equal volumes of acid and alkali would give you a 6 degree celsius rise.

 

[Metanoia]

View attachment 51086

Form equation first

2NaCl + 2H2O --> 2NaOH + Cl2 + H2

Then its a simple mole calculation question involving 58.5 kg of NaCl.

 

[rk_butterfly]

chemistry 9701 topical questions plzzzz
urgent

 

[My Name]

chemistry 9701 topical questions plzzzz
urgent

Check here
https://www.xtremepapers.com/community/threads/as-chemistry-topical-finally-here.23520/
(PS only MCQ's answers are there :/)

 

[princess Anu]

Temperature increase (due to heat of neutralization) should still be 6 degree celsius.

Expt 1: 50cm3 of acid + 50 cm3 of alkali (0.05 mol of water formed, releasing heat)
Expt 2: 100cm3 of acid + 100 cm3 of alkali (0.1 mol of water formed, releasing heat)

Basically you are generating 2 twice the amount of heat in expt 2, but its used to heat up twice the volume of solution. So temperature rise is the same in both experiments.

More importantly in this question, mixing any equal volumes of acid and alkali would give you a 6 degree celsius rise.

The reason being? if we use for example 50/4 of acid and 50/4 for alkali temperature rise will be 3 ,no?

 

[princess Anu]

Form equation first

2NaCl + 2H2O --> 2NaOH + Cl2 + H2

Then its a simple mole calculation question involving 58.5 kg of NaCl.

I don't understand why making this equation? shouldn't we make the anode cathode equations? :S

 

[Metanoia]

The reason being? if we use for example 50/4 of acid and 50/4 for alkali temperature rise will be 3 ,no?

Generally ,

heat released during neutralization = heat used to raise temperature of solution

moles of water formed x heat of neutralization = mass of solution x heat capacity of solution x temperature change

From expt 1,
(0.05) x heat of neutralization = 100 x heat capacity of solution x temperature change of expt 1

From expt 2,
(0.1) x heat of neutralization = 200 x heat capacity of solution x temperature change of expt 2

Take the eqn 2 and divide it by eqn 1

(0.1) x heat of neutralization ..........200 x heat capacity of solution x temperature change of expt 2
--------------------------------- =.... -----------------------------------------------------------------------
(0.05) x heat of neutralization .......100 x heat capacity of solution x temperature change of expt 1

You will end up with,
temp change of expt 1 = temp change of expt 2