Chemistry: Post your doubts here!

[nehaoscar]

Why won't amide ions be present?

 

[nehaoscar]

I know that 3 is wrong obviously
But the 1H3+ ion ... does it have -2 neutrons?? Like how many neutrons does it have?

 

[nehaoscar]

why is 2 wrong?
More H+ concentration = more acidic ... so why is it wrong?

 

[nehaoscar]

How are 2 and 3 also correct?
What is the intermediate formed? Like it's formula?

 

[Turki AbdulAziz]

View attachment 54569
How are 2 and 3 also correct?
What is the intermediate formed? Like it's formula?

Heres the intermediate. As you can see the oxygen carries a negative charge and since it has a lone pair it acts as a nucleophile.

 

[nehaoscar]

How to do????

 

[shazmina]

Option 2 is a salt, so it will be found in the flask. The question specifies on the distillate.

Thank you so much

 

[shazmina]

Help please........ the ans is B

Which of these equations represents the reaction of sulphur dioxide with an excess of aqueous

sodium hydroxide?

A SO2 + NaOH ----> NaHSO3

B SO2 + 2NaOH -------> Na2SO3 + H2O

C SO2 + 2NaOH ------> Na2SO4 + H2O

D SO2 + 2NaOH -----> Na2SO4 + H2

Why cant it be reaction C???

 

[nehaoscar]

Can it not also be D? Why is D wrong?

 

[nehaoscar]

Why does decomposition temperature increase?

 

[nehaoscar]

How??

 

[Falconwing]

How is 3 also correct?
V3+ = 20 electrons = 1s2 2s2 2p6 3s2 3p6 4s2 ... so it doesn't have unpaired electrons :/

You forgot 3d.

View attachment 54563
Why not the others? what would they give?

Group II metal sulphate solubility decreases down the group, so Barium will give a white precipitate (insoluble)

View attachment 54564
How to do??

3x10^-3 reacts with 2x10^-3 so 3 moles of TlNO3 reacts with 2 moles of NH4VO3. Each Ti will give 2 electrons, giving 6 electrons in total. V in Vo3- is +5, so those 6 electrons will be divided between 2 VO3s, each will get reduced to +2.

View attachment 54565
Why won't amide ions be present?

They will form NH3 immediately.

View attachment 54566
I know that 3 is wrong obviously
But the 1H3+ ion ... does it have -2 neutrons?? Like how many neutrons does it have?

None. Hydrogen doesn't usually have neutrons, hence the 1 atomic mass.

View attachment 54571
How to do????

Mass of gas is 1.32g, and usually NO2:O2 ratio is 4:1. So, taking mass of no2 as x, and O2 as 1.32 - x, you get (x/46) / ((1.32-x)/32) = 4. Solving which gives you x = 1.12g. 1.12 / 46 gives 0.0243 something. Ratio of MO:NO2 is 1:2, so nMO = 0.0122. 0.0122 = 2-1.32 / Mr gives you Mr = 55.9 almost. 55.9 - 16 gives you around 39.9, which is very near to the atomic mass of Ca. (you will get 40.1 if you don't round off things)

 

[nehaoscar]

Why and how D?
If it's D then the Carbon before the R will only have 3 bonds :O
Why not B?

 

[Falconwing]

View attachment 54575
Why and how D?
If it's D then the Carbon before the R will only have 3 bonds :O
Why not B?

Why would it have 3 bonds? It has 4. (2 with one carbon, 1 with the top ethyl group, 1 with the bottom one) Besides, if it was B, then it would still possess cis-trans isomers.

 

[alevelpleasebegood]

Hi. Why is 2 a correct statement? Catalyst doesn't affect the yield of product isn't it? Answer is 1 and 2 are correct.
http://postimg.org/image/5sln0vven/

 

[nehaoscar]

Why would it have 3 bonds? It has 4. (2 with one carbon, 1 with the top ethyl group, 1 with the bottom one) Besides, if it was B, then it would still possess cis-trans isomers.

How would it possess cis trans if it was B?

 

[Falconwing]

Help please........ the ans is B

Which of these equations represents the reaction of sulphur dioxide with an excess of aqueous

sodium hydroxide?

A SO2 + NaOH ----> NaHSO3

B SO2 + 2NaOH -------> Na2SO3 + H2O

C SO2 + 2NaOH ------> Na2SO4 + H2O

D SO2 + 2NaOH -----> Na2SO4 + H2

Why cant it be reaction C???

C isn't balanced. 4 O in reactants, 5 in products.

 

[Falconwing]

How would it possess cis trans if it was B?

It's complicated. http://www.chemguide.co.uk/basicorg/isomerism/ez.html#top

 

[Falconwing]

Hi. Why is 2 a correct statement? Catalyst doesn't affect the yield of product isn't it? Answer is 1 and 2 are correct.
http://postimg.org/image/5sln0vven/

The catalyst in experiment 1 could be faster (reduces activation energy more) than the one in 2. It has to do with speed, not yield. It would still stop at the same place as experiment 1, just taking more time.

 

[alevelpleasebegood]

The catalyst in experiment 1 could be faster (reduces activation energy more) than the one in 2. It has to do with speed, not yield. It would still stop at the same place as experiment 1, just taking more time.

Got it. Thanks