Chemistry: Post your doubts here!

[A*****]

View attachment 63707
QUESTION 35 ANWER IS OPTION D THAT IS 1

35 or 39?

 

[saitama]

can anyone predict solids and solutions for 34

 

[blymphocytes]

Guidance on how to solve these question.
17. 71.0 g of chlorine, Cl 2, react with an excess of sodium hydroxide solution at a particular temperature. The reaction produces exactly 35.5 g of product X.
What is product X?
A H 2O B NaCl C NaCl O D NaCl O3

8. Sulfur can be oxidised in two ways.
S(s) + O2(g) → SO2(g) ∆H o = –296.5 kJ mol–1 2S(s) + 3O2(g) → 2SO3(g) ∆H o = –791.4 kJ mol–1

Sulfur trioxide can be made from sulfur dioxide and oxygen.

2SO2(g) + O2(g) → 2SO3(g)

What is the standard enthalpy change for this reaction?
A –1384.4 kJ mol–1 B –989.8 kJ mol–1 C –494.9 kJ mol–1 D –198.4 kJ mol–1

 

[Hamnah Zahoor]

17. 71.0 g of chlorine, Cl 2, react with an excess of sodium hydroxide solution at a particular temperature. The reaction produces exactly 35.5 g of product X.
What is product X?
A H 2O B NaCl C NaCl O D NaCl O3

When ever chlorine gas is involved Ar of Chlorine 71.0 is to be used
Make up equations for both
3Cl2 + 6NaOH----------> NaClO3 + 5NaCl + 3H2O
Moles of chlorine 71/71= 1 mole
Moles of chlorine ratio NaClO3
Cl2: NaClO3
3 : 1
(1/3)*(106.5) = 35.5 g
Thus D is the correct option.

 

[blymphocytes]

T

When ever chlorine gas is involved Ar of Chlorine 71.0 is to be used
Make up equations for both
3Cl2 + 6NaOH----------> NaClO3 + 5NaCl + 3H2O
Moles of chlorine 71/71= 1 mole
Moles of chlorine ratio NaClO3
Cl2: NaClO3
3 : 1
(1/3)*(106.5) = 35.5 g
Thus D is the correct option.

Thanks Hamnah .......could you please explain the next one as well?

 

[Hamnah Zahoor]

T

Thanks Hamnah .......could you please explain the next one as well?

 

[blymphocytes]

View attachment 63709

Thank you so much!! <3
You're amazingg xoxo

 

[Hamnah Zahoor]

Thank you so much!! <3
You're amazingg xoxo

I am glad it helped you.

 

[Hamnah Zahoor]

View attachment 63707
QUESTION 35 ANWER IS OPTION D THAT IS 1

For statement 1 The following website will help you understand it in a more better way
https://www.chemguide.co.uk/mechanisms/nucadd/hcn.html


Thus, Statement 1 correct.

For statement 2 :
The initiating step is the nucleophile CN- attacking the partial positive carbon NOT the proton (H+) being transferred to oxygen.
For statement 3 :
Only aldehydes or ketone react with the Cyanide ion not esters. ( thus only one group reacts)

 

[innovative_1]

Can someone plsss tell how to balance this equation by oxidation number?

 

[A*****]

Can someone plsss tell how to balance this equation by oxidation number?

It is easier to do it by balancing electrons

 

[innovative_1]

It is easier to do it by balancing electrons

Yeah i totally agree with u i can even easily solve A2 electrochemistry lol but this one i just can't able to form half equations plss can u just show it's working i would get it

 

[A*****]

Yeah i totally agree with u i can even easily solve A2 electrochemistry lol but this one i just can't able to form half equations plss can u just show it's working i would get it

Such equations are very odd...I think we have to do them by hit and trial method

 

[innovative_1]

Such equations are very odd...I think we have to do them by hit and trial method

I never heard abt this method before

 

[dumbledore.]

6 A substance commonly found in the house or garden has the following properties.
• It is combustible.
• It is an electrical insulator.
• It melts over a range of temperature.
What could the substance be?
A brass
B paper
C poly(ethene)
D silicon(IV) oxide
Ans is C

 

[A*****]

I never heard abt this method before

That is simple guessing...putting the values given in the options one by one and seeing if the equation balances
https://chemtutorial.wordpress.com/tag/hit-and-trial-method/

 

[A*****]

6 A substance commonly found in the house or garden has the following properties.
• It is combustible.
• It is an electrical insulator.
• It melts over a range of temperature.
What could the substance be?
A brass
B paper
C poly(ethene)
D silicon(IV) oxide
Ans is C

Which year is it?

 

[Hamnah Zahoor]

Which year is it?

oct/nov/2008

 

[A*****]

Can someone plz help me with this one?

 

[Metanoia]

Can someone plz help me with this one?View attachment 63717

Note that except for B, the dipoles for the other 3 options can be viewed as cancelling each other out