ICSE − Q & A

How can we compare the stability of compunds of an element? (For example if Hydrogen and Na are present with oxygen. Will it combine with Na or H and why?)

in concise chemistry pg:98 electrolysis of nacl  at the cathode hydrogen is dischared  but there is high concentration of na+ than h+
please can anyone explain the reason

So many people are having doubts here!
I will frequently upload interesting questions and chapter wise analysis so you know what to learn.
I will start of with basic chemistry:
Equations.
1)
Do not mug them up. Just don't. You will mess up.
Understand equations. Understand their products. Learn balancing (use youtube for reference).
Suppose the reaction of HCl (conc) and K2Cr2O7 (acidified) is asked.
Understand what happens with reaction with conc HCl. Metallic chloride, chlorine gas and water is formed. Now K2Cr2O7 has two metals so 2 metallic chloride will be formed. KCl and CrCl3. Now as all water and oxygen will be used up to prepare water, number od HCl molecules = 2x the number of oxygen atoms.
Hence we have 14 HCl.
We have 2 K, so 2KCl will be formed.
We have 2 Cr, so 2CrCl3 will be formed.
This leaves 10Cl atoms = 5Cl2.
If you understand equations and know products, you can form any equation you want, even if you dont remember balancing or haven't learnt it.

2) Do not forget to write concentrated , dilute, acidified, alkaline or alcoholic. These carry 1/2 marks. the conditions I.e. temperate, pressure, catalyst, promoter. Remember if an equation is reversible or not. Remember if reaction is exothermic or endothermic. If it is the former, make a triangle ∆ with the products. If it is latter, make a triangle ∆ on the arrow.
That's all from this. Respond if you have a doubt regarding equations. I'll post chapter 1 and 2 analysis in the morning.

I've seen many people here saying that physics paper was tough according to me it was easy it depended on numerical so and even descriptive part of 40marks carried objective questions can you please tell me how it turned out to be a tough one for you guys?!?!?!?!?

http://www.respaper.com/ved0_ssk_respaper_pongala/2543-pdf.html?cmd=conv pls give the ans. of Q1B5

+ 2 more questions by disha95  

Is the gas responsible for yellow color in acid rain-SO2 and the gas responsible for acid rain is-NO2??
asked by Disha Ghatak (disha95) 7 years ago
1

The element having the most metallic character among the alkaline earth metals-is it Radium or Barium??
asked by Disha Ghatak (disha95) 7 years ago
1

Hey any other publisher for biology? plz name them?other than selina

Will any questions be repeated from previous years boards????

What is the difference between orbit and orbital?

can anyone explain me the s , p , d , f  orbit rules ??

You are provided with only one alkali calcium hydroxide . Two white salts sodium chloride and ammonium chloride are given. How can you identify them?