Chemistry: Post your doubts here!

[Autumn98]

What's the answer?

It's D

 

[Falconwing]

Does anyone know the answer and the reason behind it?
View attachment 54338

It's probably A, strong acid + strong base = highest enthalpy, weak acid + strong base = lower enthalpy and so on.

 

[Falconwing]

Why is 3 wrong?

v1 / 298 = v2 / 323 so v2 = 1.08v1
it won't be doubled. You were probably taking it in celsius instead of kelvin

 

[fantastic girl]

I think it might be because if the pH is 14, there is a very high concentration of hydroxide ions. This would lead to OH- ions having high chances of collision with the aluminum and barium nitrate. It's just a guess I'm not sure though

yea there wud high conc. of OH- ions but why wud it collide with Al and Ba(NO3)2 ? :S

 

[princess Anu]

why is B wrong?

 

[princess Anu]

how to find the oxidation state of Ag in this ion..? is shud come out to be +1:/ thou i'm getting -1
help!!!

 

[Falconwing]

why is B wrong?

If B was to be true, then purple vapour would've formed with sodium iodide in the second row too

how to find the oxidation state of Ag in this ion..? is shud come out to be +1:/ thou i'm getting -1
help!!!

Sulphur has a charge of +2 in this case, so S2O3 has a total charge of -2 which becomes -4 since there are two of them. The total charge of the entire molecule is -3, so Ag must be +1.

 

[qwertypoiu]

yea there wud high conc. of OH- ions but why wud it collide with Al and Ba(NO3)2 ? :S

Just wanna say again I'm not sure but:
If aluminium hydroxide and barium hydroxide are being formed by reaction with water it's probably got to do with OH- ions from water forming dative bond with the metal atoms...
So if there is more such OH- ions in the mixture, there would probably be a higher rate of occurance for this bond formation... Due to random movement and collision and bla bla the high concentration of the OH- increases reaction rate. I suppose. I hope someone else has a more thorough answer.

 

[69ermalik007]

Why is A incorrect?

 

[The Sarcastic Retard]

Why is A incorrect?

View attachment 54346

n of ethanol : 0.05 : n of ethanal.
m of ethanal : 0.05 * 44 = 2.2g
100% ---> 2.2g
60% -----> ?
60% x 2.2 = 1.32g

 

[princess Anu]

answer given is B.. can someone explain why 2 is correct?

 

[princess Anu]

how to do this? do we have to look for a small change in ionisation energies or what ?

 

[ahmedish]

can someone explain how to do J14 v1 q8,9 and 29? thanks.

 

[bubbles1997]

Aoa. Does anyone know what will be in the practical of chemistry 34?

 

[bubbles1997]

Hi All! Please help us in tomorrow's chemistry practical.
Feel free to post anything related.
https://www.xtremepapers.com/community/threads/as-chemistry-2015-m-j.41585/

 

[phanttasy]

i have problem while solving question number b iii)
your help will be much appreciated

 

[Mathemagical]

answer given is B.. can someone explain why 2 is correct? View attachment 54350

Option 2 is correct because it takes less energy for HI to dissociate into H2 and I2 so there is a greater proportion of these gases in the equilibrium. Hence, the value of Kp is smaller.

 

[princess Anu]

how do we get these ratios?

 

[The Sarcastic Retard]

how do we get these ratios?

Is D the answer?

 

[princess Anu]

It's B

Is D the answer?[/QUOTE}