ANSWERING ALL BIO/CHEM PAPER 1 DOUBTS :)

[сᴏᴏʟ сяуѕтᴀʟѕ]

Thank you Cool Crystals, but can you please explain why the answer is Sulphur Dioxide (D) and not nitrogen (B) (Yes you are right).

And thanks for the explanation to my second doubt

Well the thing is nitrogen is also present in air...infact the other 3 gases can be formed...bcoz carbin dioxide is present in the air...and when nitrogen reacts with oxygen and high temperature oxides of nitrogen can also be formed!
BUT the formula for ethanol is C2H5OH, there is no SO2 in it...so sulphur dioxide can't be formed...

hope that clears your doubt
feel free to ask if still it doesn't!

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Yet again, another doubt. Please help me with question 13 in the PDF attached. Thanks

the answer is D...
bcoz as the solution is concentrated, chlorine will be discharged which makes the universal indicator colorless! chlorine is discharged at the positive electrode...
the other electrode the color changes to blue...which is in the case of alkali!

 

[Besterlinks]

the answer is D...
bcoz as the solution is concentrated, chlorine will be discharged which makes the universal indicator colorless! chlorine is discharged at the positive electrode...
the other electrode the color changes to blue...which is in the case of alkali!

Why does chlorine make the indicator colourless? Its pH is 11.7!

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Why does chlorine make the indicator colourless? Its pH is 11.7!

test for chlorine is?
it bleaches the litmus paper...i.e it makes the universal indicator colorless!

 

[Besterlinks]

Oh, okay. Thanks.

 

[Besterlinks]

Guys, found this MCQ paper on xtremepapers forums itself. Contains some predicted questions for our bio/phys/chem MCQs. Although physics is over, lets solve the MCQs for bio and chem, discuss our answers and see if we can solve each other's doubts. Yeah?

 

[mamoon123]

What does lag, log and expotential mean? It's in biology, something related to the sigmoid curve.

 

[Besterlinks]

Please help me with question 21 of the attached PDF.

 

[Warrior66]

Besterlinks, AOA, ok first of all you should see which gas is neutral which means that it won't react with the solution. This gas as the question shows is NITROGEN. Right? But it has ammonia with it which means that it will dissolve in the water that's why the solution rises up a little because water and ammonia have reacted. But if you see for the other options, the solution is sodium hydroxide which would react with CO2 and SO2 because these are acidic gases! Therefore your answer would be D. Hope this explanation helps! Good luck!

 

[Besterlinks]

Warrior66, Yeah that helps a lot. Thanks

 

[L.V.D]

hey Cool crystals i also have Biology doubts and second of all I really like the way you explain its really helpful
which are from winter 2011 (11) q. 12 24 24 37
summer 2006 q. 21
winter 2006 q. 14
summer 2007 q. 35 & 28
winter 2007 q. 16- 25- 28
winter 2010 (11) q. 29 27

 

[svenas]

Well...it says ALL the Oxygen in the dry air is reacted...the percentage of Oxygen i air is 20%
% of air remainingis 100 - 20 = 80%
Volume of air remaining = 120 cm3
we will cross multiply!
% of remaining air - 80% Total air - 100%
Volume of remaining air - 120 cm3 Volume of total air - ?
? = 120 * 100/80 = 150 cm3
and so the answer is B....

got it?

plz help me in this paper..http://www.xtremepapers.com/papers/...nal O Level/Biology (5090)/5090_w11_qp_11.pdf
answers: http://www.xtremepapers.com/papers/...nal O Level/Biology (5090)/5090_w11_ms_11.pdf
questions 9, 14, 21, 32, 33, 40...
THNAKS!!!

 

[Student of the year]

What does lag, log and expotential mean? It's in biology, something related to the sigmoid curve.

LAG: this is the initial part of the sigmoid curve (the straight line near the y axis) of a typical sigmoid curve
LOG: also called exponential) is the middle part of the curve, this shows an increase

hope u understood,& this is enough,
if not ask again.

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

hey Cool crystals i also have Biology doubts and second of all I really like the way you explain its really helpful
which are from winter 2011 (11) q. 12 24 24 37
summer 2006 q. 21
winter 2006 q. 14
summer 2007 q. 35 & 28
winter 2007 q. 16- 25- 28
winter 2010 (11) q. 29 27

Assalam-o-alaikum wr wb...

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

hey Cool crystals i also have Biology doubts and second of all I really like the way you explain its really helpful
which are from winter 2011 (11) q. 12 24 24 37
summer 2006 q. 21
winter 2006 q. 14
summer 2007 q. 35 & 28
winter 2007 q. 16- 25- 28
winter 2010 (11) q. 29 27

aoa wr wb..

i tried my best to explain...if still any doubt, feel free to ask

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

plz help me in this paper..http://www.xtremepapers.com/papers/...nal O Level/Biology (5090)/5090_w11_qp_11.pdf
answers: http://www.xtremepapers.com/papers/...nal O Level/Biology (5090)/5090_w11_ms_11.pdf
questions 9, 14, 21, 32, 33, 40...
THNAKS!!!

Assalam-o-alaikum wr wb...

Hope this clears everything

 

[svenas]

Assalam-o-alaikum wr wb...
View attachment 12479View attachment 12480View attachment 12481View attachment 12482View attachment 12483View attachment 12484
Hope this clears everything

THANKS A BUNCH!
For the last question, if the genotype is possible to come then automatically the probability is 1?....or to be sure I understood this question, can u gv me example where probability is not 1?

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

THANKS A BUNCH!
For the last question, if the genotype is possible to come then automatically the probability is 1?....or to be sure I understood this question, can u gv me example where probability is not 1?

no need...it's okie! juss remember me in your prayers

yeahp!
what is the probability that one of these offspring that shows the recessive characteristics is heterozygous?

 

[svenas]

no need...it's okie! juss remember me in your prayers

yeahp!
what is the probability that one of these offspring that shows the recessive characteristics is heterozygous?

aha now I got it thanks..

 

[svenas]

aha now I got it thanks..

surely I'll remember u in my prayers.