Chemistry MCQ thread...

[Anonymousx3]

Which of the following statement(s) is/are true?
1 When SiCl4 is added to water, a precipitate is formed.
2 sulfur has a higher melting point than phosphorus because the intermolecular
attractions are stronger.
3 When AlCl3 is dissolved in water, [Al(H2O)5(OH)]2+(aq) is one of the ions
formed.

B?
1 and 2 are right, I think.

 

[Xthegreat]

nope, its 2 and 3.

SiCl4 dissolves in water to give a strong acid, no ppt

 

[Zishi]

Which of the following statement(s) is/are true?
1 When SiCl4 is added to water, a precipitate is formed.
2 sulfur has a higher melting point than phosphorus because the intermolecular
attractions are stronger.
3 When AlCl3 is dissolved in water, [Al(H2O)5(OH)]2+(aq) is one of the ions
formed.

B?
1 and 2 are right, I think.

A. All 3 are correct.

nope, its 2 and 3.

SiCl4 dissolves in water to give a strong acid, no ppt

It also forms SiO2. Water can't dissolve it.

 

[MHHaider707]

I think its 1 , 2 and 3!!

All are true.....

But i m not sure about it...

 

[Zishi]

I think its 1 , 2 and 3!!

All are true.....

But i m not sure about it...

Yep. They ALL have to be true...

 

[Anonymousx3]

Doesn't the [Al(H2O)5OH]2+ ion form when Al2Cl6 is dissolved in water, not AlCl3?
Or are they the same thing and I'm just confusing myself?

 

[MHHaider707]

Al2Cl6 is formed due to dimerization of AlCl3, so they should be same things . . .

Correct me if i m wrong!!

 

[xHazeMx]

Which of the following statement(s) is/are true?
1 When SiCl4 is added to water, a precipitate is formed.
2 sulfur has a higher melting point than phosphorus because the intermolecular
attractions are stronger.
3 When AlCl3 is dissolved in water, [Al(H2O)5(OH)]2+(aq) is one of the ions
formed.

i m not sure about 1 but statements 2 and 3 are correct

 

[Zishi]

Doesn't the [Al(H2O)5OH]2+ ion form when Al2Cl6 is dissolved in water, not AlCl3?
Or are they the same thing and I'm just confusing myself?

No, it also forms when AlCl3 dissolves in water. First of all [Al(H2O)6]3+ forms, this ion is acidic, so then it forms [Al(H2O)5OH]2+

Al2Cl6 is formed due to dimerization of AlCl3, so they should be same things . . .

Correct me if i m wrong!!

Right.

 

[MHHaider707]

1 is also correct as on dissolving in water SiCl4 will give HCl and SiO2....

SiO2 is insoluble so it will be the precipitate!!

SiCl4 + 2H2O------> SiO2 + 4HCl

 

[Anonymousx3]

k, thanks guys, I finally got it. ;p

 

[xHazeMx]

what is the colour of HBr,HI and HAs

 

[sakibfaiyaz]

Colourless

 

[xHazeMx]

Colourless

all of them?

 

[xHazeMx]

why is it 1 only???

 

[ninjas4life]

why is the answer a?

 

[xHazeMx]

why is the answer a?

P has the largest ionic and atomic radii in its same period of periodic table. it's a fact so learn it

 

[Zishi]

why is it 1 only???

Because benzoic acid will be formed from 2, which is readily soluble in hot water, but is poorly soluble in cold one.

Option number 3 is a ketone, so that can't be oxidised.

 

[ninjas4life]

 

[xHazeMx]

why is the answer B ?? though the bond energy of A is higher !