Chemistry MCQ (Paper 1) Discussion

[karthik]

so how many pairs of electrons were shared? CH3COCH3CH2CH2CO ( double bond for last CO )

I am damn sure its 16

 

[karthik]

O^-2 + 2 e ----> O2
2C + 2O2 -----> 2CO2

those two were correct i think

No .....
O^-2 + 2 e ----> O2 is right however 2C + 2O2 -----> 2CO2 is the remaining in the container which reacts up and forms !!! that was pretty tricky!!

 

[karthik]

the answer is 13 pairs of electrons!!

No it is 17

NO its 16

 

[Shiki Misaki]

so how many pairs of electrons were shared? CH3COCH3CH2CH2CO ( double bond for last CO )

I am damn sure its 16

I put 16 too.

 

[basch]

You ARE WRong in two answers you gave karthik. (i)the body of aeroplanes are made up of an aluminium alloy(I just checked it out on the net).
(ii)at the anode oygen is formed and with time the oxygen reacts with the carbon anode.this is why the anode has to be replaced with time

 

[axhynic]

i'v corrected the equation in my original post [oxygen ions doesn't gain, but looses electrons to form oxygen >_<]

also

You ARE WRONG in two answers you gave karthik. (i)the body of aeroplanes are made up of an aluminium alloy(I just checked it out on the net).
(ii)at the anode oxygen is formed and with time the oxygen reacts with the carbon anode.this is why the anode has to be replaced with time

i say this too

the answer is 13 pairs of electrons!!

No it is 17

NO its 16

no its 17

 

[Shiki Misaki]

Yeah there are 17 bonds. Just realised my mistake.

 

[Heshna]

What are the answers for n0. 23 and n0.26 ???

 

[basch]

what were the questions?

 

[Shiki Misaki]

No 23) The position of metal M in the reactivity series.
Which method will be used to extract M from its ore? *Bla Bla Bla*

No 26) An apparatus was given. Chlorine is passed through the tube. After a short time, coloured substances are seem at P,Q and R.
The question was 'What are these coloured substances?'.


For 26, I've put C.
At P - Red Brown Vapour
At Q - Violet Vapour
At R - Black Solid

I'm unsure about my answers. :S

 

[basch]

for the number 26 your answer is correct and as for the number 23,the answer should be: extraction from its metal oxide

 

[Prince III]

for Q.26 answer is C

but what were the other options in question 23 ?

 

[Shiki Misaki]

for No. 23

A. Electrolysis of its aqueous sulfate
B. Electrolysis of its molten oxide
C. Reduction of its oxide by heating with coke
D. Reduction of its oxide by heating with hydrogen.

 

[rose1700]

for No. 23

A. Electrolysis of its aqueous sulfate
B. Electrolysis of its molten oxide
C. Reduction of its oxide by heating with coke
D. Reduction of its oxide by heating with hydrogen.

it should be B

 

[Shiki Misaki]

Got it wrong then....

 

[creative22]

why B is wrong ?

 

[Shiki Misaki]

why B is wrong ?

I meant to say that I didn't put B.

 

[creative22]

okay sorry didnt get you first time
the answer should be B because it is similar method to extraction of aluminium
aluminium is also extracted by the same way

sine the electrolyte wont having H+ and OH- ions because it does not have aqeous solution ,so simply oxygen would be released at anode and metal M would migrate to cathode

 

[Shiki Misaki]

Thanks creative22.
Never understood electrolysis by the way. xD