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Biology; Chemistry; Physics: Post your doubts here!

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the colour changes from "orange to green" and "purple to colourless" when "potassium dichromate" and "potassium mangnate" are added to a reducing agent respectively!(they are oxidising agents)
and the colour changes from colourless to brown when potassium iodide is added to any oxidising agent(it is a reducing agent)
Thanks a lot......:DDDDD I get it now.....
 
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the colour changes from "orange to green" and "purple to colourless" when "potassium dichromate" and "potassium mangnate" are added to a reducing agent respectively!(they are oxidising agents)
and the colour changes from colourless to brown when potassium iodide is added to any oxidising agent(it is a reducing agent)
How to give trophies in this forums??
 
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What if we don't practice graph questions from the ATP?
Because I don't have past papers available in printed form. Do I have to print them or it's ok to just leave making graph?
Atleast u should try 4 graphs frm the latest years !! Specially for physics !!
 

asd

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It's A. can't be D
You see, if any of the alleles I(A) or I(B) combines with I(O) it will lead to blood group A or B, respectively (because I(O) is recessive, I(A) and I(B) dominant). With option D, there is a possibility of getting a blood group B (when B combines with O). So D is not an option. Other options also have the possibilities of getting Blood group B. Only option left is A.
 
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2 The labels fell off two bottles each containing a colourless solution, one of which was sodium carbonate solution and the other was sodium chloride solution.
The addition of which solution to a sample from each bottle would most readily enable the bottles to be correctly relabelled?
A ammonia
B hydrochloric acid
C lead(II) nitrate
D sodium hydroxide

Pls explain
 
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2 The labels fell off two bottles each containing a colourless solution, one of which was sodium carbonate solution and the other was sodium chloride solution.
The addition of which solution to a sample from each bottle would most readily enable the bottles to be correctly relabelled?
A ammonia
B hydrochloric acid
C lead(II) nitrate
D sodium hydroxide

Pls explain

is it an MCQ?? :eek:
 
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2 The labels fell off two bottles each containing a colourless solution, one of which was sodium carbonate solution and the other was sodium chloride solution.
The addition of which solution to a sample from each bottle would most readily enable the bottles to be correctly relabelled?
A ammonia
B hydrochloric acid
C lead(II) nitrate
D sodium hydroxide

Pls explain

the ans is (B) here cuz sodium carbonate comes in contct with HCl it will give off effervesnce(bubbling)....how ever sodium chloride will ve no reaction...!!!
 
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the ans is (B) here cuz sodium carbonate comes in contct with HCl it will give off effervesnce(bubbling)....how ever sodium chloride will ve no reaction...!!!
Why do you need effervescence on this question???? I really don't understand this labels
 
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Why do you need effervescence on this question???? I really don't understand this labels

tell the question and year plz...:D
i think it should be C btw.

it would a ppt reaction with NaCl with lead(2)cl will form white compunds..:D
and nothing would happen to the other one..:D
 
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Why do you need effervescence on this question???? I really don't understand this labels

yar itz like this ke on is NaCO3....while other is NaCl....n v need to differntiatie b/t the two so tht corect labls cld be postd..!!
 
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