Chemistry MCQ thread...

[Zishi]

Astatine (At) is a Group VII element. Its properties are not easily studied due to its
short half life and low natural abundance. However, its properties can be deduced
from the trends of other Group VII elements. Which of the following statements
about astatine are likely to be correct?
1 HAt is a stronger acid compared to HCl.
2 At2 disproportionates in cold dilute sodium hydroxide to yield AtO3
- and At - as
major products.
3 Potassium astatide forms a precipitate with silver nitrate quickly and can dissolve
in dilute aqueous ammonia solution.

A

no way ! :%)

LOL!

 

[xHazeMx]

LOL! Maybe I'm wrong, then. I'm sure that option number 3 is correct. So if 1 and 3 are correct, then obviously 2nd may be correct.

option 3 happens only with AgCl with Cl ions but not with As ions and i m sure that 2 is wrong :crazy: I GUESS

 

[Zishi]

LOL! Maybe I'm wrong, then. I'm sure that option number 3 is correct. So if 1 and 3 are correct, then obviously 2nd may be correct.

option 3 happens only with AgCl with Cl ions but not with As ions and i m sure that 2 is wrong :crazy: I GUESS

Oh, yes. I was damn confused. lol My bad. D is the answer.

 

[xHazeMx]

LOL! Maybe I'm wrong, then. I'm sure that option number 3 is correct. So if 1 and 3 are correct, then obviously 2nd may be correct.

option 3 happens only with AgCl with Cl ions but not with As ions and i m sure that 2 is wrong :crazy: I GUESS

Oh, yes. I was damn confused. lol My bad. D is the answer.

think twice Zishi because i trust all ur answers 100 % ( excluding the last question )

 

[Zishi]

think twice Zishi because i believe in all ur answers 100 % ( excluding the last question )

LOL! The thing is today I'm just looking at questions and just answering them without thinking. Maybe I need a sleep. ardon:

 

[MHHaider707]

http://www.xtremepapers.me/CIE/Internat ... 9_qp_1.pdf


anyone plz help me in Q. 23 n 25

 

[xHazeMx]

think twice Zishi because i believe in all ur answers 100 % ( excluding the last question )

LOL! The thing is today I'm just looking at questions and just answering them without thinking. Maybe I need a sleep. ardon:

yeah, i think u should take rest for some time because ''CONFUSION'' just EATS INTO UR SUPER MIND !!

 

[Xthegreat]

and please help me with oct nov 04 no 10 11 12 and 21.. i cant paste it here because there are pictures and tables.. [/quote][/quote][/quote]

I have the same query regarding 19. Please can someone tell me how to solve it???? Pleease [/quote]


O/N 04
Q 10 - partial pressure of gas1 = (num.of mole of gas1)/(num. of mole of total gas) x total pressure
ans : D

Q11
ans : A
- the equilibrium will shift to the left hand side when the concentration of acid increases (H+)
- B is wrong because the oxidation number of elements remain the same
- C is wrong because catalyst ONLY speeds up reaction, no effect whatsoever on the yield
- D is wrong because the unit of Kc is (moldm-3)^-2

Q12
ans : B
- A is wrong because at higher temp, the highest point of the graph is always lower
- C is wrong because there should not be a sharp bend near the end of the graph and it's too close to zero
- D is wrong becasue the graph can never be shaped this way.

Q21
chiral center means a carbon bonded to 4 different groups and obviously D is bonded to 2 same group. ( 2 phenol group )

 

[hassam]

its D

 

[Zishi]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_s09_qp_1.pdf


anyone plz help me in Q. 23 n 25

Q23: B - because the bond changed from a double one to a single one.

Q25: B - because nucleophilic substitution takes place in this reaction, alcohol is formed.

 

[aleem420]

2 Use of the Data Booklet is relevant to this question.
A typical solid fertiliser for use with household plants and shrubs contains the elements N, P, and
K in the ratio of 15 g : 30 g :15 g per 100 g of fertiliser. The recommended usage of fertiliser is 14 g
of fertiliser per 5 dm3 of water.
What is the concentration of nitrogen atoms in this solution?
A 0.03 mol dm–3
B 0.05 mol dm–3
C 0.42 mol dm–3
D 0.75 mol dm–3

can anyone help me with it???? plz

 

[Zishi]

think twice Zishi because i believe in all ur answers 100 % ( excluding the last question )

LOL! The thing is today I'm just looking at questions and just answering them without thinking. Maybe I need a sleep. ardon:

yeah, i think u should take rest for some time because ''CONFUSION'' just EATS INTO UR SUPER MIND !!

Nah, no confusion...I'm just tired, I guess. :unknown:

 

[abdullah181994]

PLEASE PLEASE ANSWER THESE QUESTIONS WITH EXPLANATION,
CORRECT ANSWER ARE
9 B , 10 D

 

[Xthegreat]

question 19

just write out the equation and balance. quite easy

(NH4)2SO4 + 4O2 -> H2SO4 + 2HNO3 + 2H2O

heyy do you have any tips and tricks on balancing equations, i really suck at that

oh well, if u ask me, my teacher said
1st, balance elements that only occur once on both side of the equation.
- so from the above eqn, that special element is N and S.
then after that you go to elements that are used more than once.
- from our eqn, the elements are O and H.

 

[xHazeMx]

Nah, no confusion...I'm just tired, I guess. :unknown:

alright a brain storming question just to wake u up
which group in the periodic table contains the element Chlorine ?
A group 1
B group 7
C group 4
D group 10

 

[MHHaider707]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_s09_qp_1.pdf


anyone plz help me in Q. 23 n 25

Q23: B - because the bond changed from a double one to a single one.

Q25: B - because nucleophilic substitution takes place in this reaction, alcohol is formed.

But how do we know that bond is shorter or longer in Q.23??

 

[MHHaider707]

Nah, no confusion...I'm just tired, I guess. :unknown:

alright a brain storming question just to wake u up
which group in the periodic table contains the element Chlorine ?
A group 1
B group 7
C group 4
D group 10

Where did u find this group 10..?? :lol:

 

[hassam]

Which of the following statements is true about hydrogen halides?
A Enthalpy change of formation becomes less exothermic down the group.
B Thermal stability increases down the group.
C Acidity of the corresponding aqueous solution decreases down the group.
D Charge density of cation decreases down the group.
Astatine is below iodine in Group VII.
Which of the following would be a correct prediction for astatine and its compounds?
A Astatine would oxidise chloride to chlorine.
B Potassium astatide would be a white crystalline solid.
C Astatine is insoluble in chloroform.
D Silver astatide reacts with concentrated aqueous ammonia to form a soluble complex.

 

[xHazeMx]

Nah, no confusion...I'm just tired, I guess. :unknown:

alright a brain storming question just to wake u up
which group in the periodic table contains the element Chlorine ?
A group 1
B group 7
C group 4
D group 10

Where did u find this group 10..?? :lol:

thats the whole point of the question LOL :lol:

 

[Zishi]

Nah, no confusion...I'm just tired, I guess. :unknown:

alright a brain storming question just to wake u up
which group in the periodic table contains the element Chlorine ?
A group 1
B group 7
C group 4
D group 10

ROFL