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Posted

here's some questions from my chem exam 2day... wondering abt the ans...=P

 

what will be produced if NaH reacts with water? is NaH flammable?!

==

is CO flammable!?

==

 

and also...CO2 mustn't called inert, isn't it?! coz the question is asking whether the 2 statements are correct...

1st- CO2 is used in fire extinguisher...

2nd- CO2 is inert n heavier than water...

 

it is a mc question,

a. both are correct with 2nd statment is the explaination of the 1st

b. both are correct but the 2nd is not an explaination

c. 1st is correct but not the 2nd

d both are incorrect....

 

thx~ asking some stupid questions again... /.\ :embarass:

Posted

I`de go with C.

 

CO2 is indeed used in fire extinguishers. but it is certainly not "Inert" :)

 

CO (carbon monoxide) will indeed burn to form carbon dioxide CO2, but it`s not what I would class as "Flamable" per se.

 

Sodium Hydride (NaH) will react with water to release the Hydrogen and make a sodium hydroxide solution, hydrogen is only flamable with an Oxidiser, pure hydrogen will not burn.

so that anyone guess what they mean by flamable :)

 

Posted

abt the CO...

is the same type of ms question as that abt CO2

which 1st statment is "Mg burns in CO2"

2nd is "CO is flammable"...

i learnt that CO n H2 is the components of town gas, so some of my frds said it should be flamable... but i am not sure abt it...

 

and how to classify sth as flammable or not?

 

another question

conc sulphuric acid reacts with NaCl, to give HCl fumes...

asking abt what does the acid act as...

A. strong acid

B. oxidizing agent

C. dehydrating agent

D. dibasic acid...

 

i hv chosen B, coz it seems that the others are not reli related to this reaction... but indeed i can't find out any change in the oxidation no of the matters...*o* or is it just becoz it is a strong acid!?

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