Chemistry MCQ thread...

[hassam]

Hydrogen chloride gas is prepared by adding concentrated sulfuric acid to
solid sodium chloride. The same method was used to prepare hydrogen
iodide but the yield is very low when concentrated sulfuric acid is added to
solid sodium iodide.
Which deductions can be made from the above?
1 Iodide is a stronger reducing agent than chloride.
2 Concentrated sulfuric acid is a weaker oxidising agent than hydrogen
chloride.
3 The reactions between the sodium halides and concentrated sulfuric
acid are redox reactions.

 

[abdullah181994]

Someone help me out!:
http://www.xtremepapers.me/CIE/Internat ... 5_qp_1.pdf

question 25, whats the difference between A and D? For PCl5 to react with the molecules, they must contain the alcohol group right?

FOR PCL5 TO REACT -OH SHOULD BE PRESENT

 

[libra94]

Hydrogen chloride gas is prepared by adding concentrated sulfuric acid to
solid sodium chloride. The same method was used to prepare hydrogen
iodide but the yield is very low when concentrated sulfuric acid is added to
solid sodium iodide.
Which deductions can be made from the above?
1 Iodide is a stronger reducing agent than chloride.
2 Concentrated sulfuric acid is a weaker oxidising agent than hydrogen
chloride.
3 The reactions between the sodium halides and concentrated sulfuric
acid are redox reactions.

is it D?? (1 only)

 

[Abdulrab]

i dont know how 2 do it !!! u do it plzz

 

[soumayya]

please do this question Q2 of Oct /Nov 08 !! its challenging

ao i think u all should try it and give me the correct answer !!! thnx please do it asap !!!

heres the link also ! http://www.xtremepapers.me/CIE/Internat ... 8_qp_1.pdf

After burning, there will be 20 cm3 of oxygen (since it is in xs), 10 cm3 of CO2 and 20 cm3 of SO2. Total = 50 cm3 of gas

After treatment with NaOH, there will be only 20 cm3 of oxygen (both CO2 and SO2 will react with NaOH, both being acidic gases)...

so, the answer is C...
Hpe zat hlpss...

 

[xHazeMx]

plz help me at this......................
help me find which transportable gas is poisonous

its OXYGEN .. obviously oxygen cant burn IN OXYGEN ..

oh buddy dont be in a fuss read the question first..................

i've done it twice before and the answer is oxygen because hydrocarbons are flammable, H2 is used as a fuel and OBVIOUSLY oxygen cannot burn in oxygen

 

[xHazeMx]

Hydrogen chloride gas is prepared by adding concentrated sulfuric acid to
solid sodium chloride. The same method was used to prepare hydrogen
iodide but the yield is very low when concentrated sulfuric acid is added to
solid sodium iodide.
Which deductions can be made from the above?
1 Iodide is a stronger reducing agent than chloride.
2 Concentrated sulfuric acid is a weaker oxidising agent than hydrogen
chloride.
3 The reactions between the sodium halides and concentrated sulfuric
acid are redox reactions.

B right ?

 

[Saturation]

Someone help me out!:
http://www.xtremepapers.me/CIE/Internat ... 5_qp_1.pdf

question 25, whats the difference between A and D? For PCl5 to react with the molecules, they must contain the alcohol group right?

FOR PCL5 TO REACT -OH SHOULD BE PRESENT

but it's present in the carboxylic acid group!

 

[xHazeMx]

Someone help me out!:
http://www.xtremepapers.me/CIE/Internat ... 5_qp_1.pdf

question 25, whats the difference between A and D? For PCl5 to react with the molecules, they must contain the alcohol group right?

FOR PCL5 TO REACT -OH SHOULD BE PRESENT

but it's present in the carboxylic acid group!

the question says that all the compounds react with PCL5 .. in (A) Y doesn't have a hydroxyl group so it will not react with PCL5. if u look to the option D u will find a hydroxyl group in all the three compounds so all of them will react with PCl5 and only compound Y will react with 2,4-DNPH ( aldehyde group )

 

[abdullah181994]

Someone help me out!:
http://www.xtremepapers.me/CIE/Internat ... 5_qp_1.pdf

question 25, whats the difference between A and D? For PCl5 to react with the molecules, they must contain the alcohol group right?

FOR PCL5 TO REACT -OH SHOULD BE PRESENT

but it's present in the carboxylic acid group!

YEAH OH IS PRESENT IN C.ACID SO IT WOULD REACT

 

[diwash]

I hope u guys have already finished the past papers and wondering how to spend tomorrow..then here is a few more MCQ's...have a look

http://chemistry.boisestate.edu/people/richardbanks/organic/mc/mcquestions317.htm

 

[Zishi]

zishi...all bond making processes are EXOTHERMIC Apart from exceptions....so formation of H-CL is most exothermic since H-Cl bond strength is high and it decreases DOWN THE GROUP ......I.E LESS EXOTHERMIC AND IN CASE OF HI IT BECOMES ENDOTHERMIC SINCE h2 and I2 BONDS INVOLVE MORE ENERGY IN BREAKING THAN THAT RELEASED ON FORMATION OF hi bond

I know this. :roll:

 

[Zishi]

Hydrogen chloride gas is prepared by adding concentrated sulfuric acid to
solid sodium chloride. The same method was used to prepare hydrogen
iodide but the yield is very low when concentrated sulfuric acid is added to
solid sodium iodide.
Which deductions can be made from the above?
1 Iodide is a stronger reducing agent than chloride.
2 Concentrated sulfuric acid is a weaker oxidising agent than hydrogen
chloride.
3 The reactions between the sodium halides and concentrated sulfuric
acid are redox reactions.

D

 

[Zishi]

B

 

[xHazeMx]

Hydrogen chloride gas is prepared by adding concentrated sulfuric acid to
solid sodium chloride. The same method was used to prepare hydrogen
iodide but the yield is very low when concentrated sulfuric acid is added to
solid sodium iodide.
Which deductions can be made from the above?
1 Iodide is a stronger reducing agent than chloride.
2 Concentrated sulfuric acid is a weaker oxidising agent than hydrogen
chloride.
3 The reactions between the sodium halides and concentrated sulfuric
acid are redox reactions.

D

yeah i agree with that now

 

[xHazeMx]

Which mixtures, on heating, produce the gas ND3?
[D = H 2
1 , an isotope of hydrogen]
1 CaO(s) and ND4Cl(s)
2 CH3CN and NaOD in D2O
3 NDH3Cl and NaOD in D2O

how 2 is possible ???

 

[abdullah181994]

http://www.xtremepapers.me/CIE/Internat ... 6_ms_1.pdf
please explain Q 4 and Q9

 

[ShootingStar]

Need help with the following question

 

[abdullah181994]

B is answer

 

[abdullah181994]

Need help with the following question

C is the answer
apply this CxHy + x+y/4...........>xCO2 +y/2 H2O
30/10=3 Carbon atoms
50/10=5 moles of O2 so apply x+y/4=5 x=3 so from here we get y=8 which is number of hydrogen so C3H8