bonding.... (1 Viewer)

[deadbeat]

a.[FONT=&quot] [/FONT]Pure nitric acid (HNO₃) is a covalent liquid that does not react with dry sodium carbonate. Yet, dilute nitric acid does. Explain this.


Something to do with solubility???? not sure.....

 

[undalay]

Pure HNO<SUB>3 </SUB>and solid NaOH.
There is no attraction between them, and their respective bonds are just too strong.

In aqueous solution, the covalent bonds in HNO<SUB>3 </SUB>and destroyed.
HNO₃ -> H⁺+ + NO₃
and electrostatic attraction of NaOH is also overcome.
NaOH -> Na⁺ + OH^-

In aqueous solution, the initial bonds are overcome by the water, and such the free H+ and OH- ions can react due to the electrostatic attraction.

something like that

 

[deadbeat]

Its Na2CO3 not NaOH, does it make a difference?

 

[undalay]

oh, then it shouldn't react.

UNless be "react" they mean dissolve.

not 100% sure.

 

[WantToDoBetter]

a.Pure nitric acid (HNO<SUB>3</SUB>) is a covalent liquid that does not react with dry sodium carbonate. Yet, dilute nitric acid does. Explain this.


Something to do with solubility???? not sure.....

Jezz, i was always under the impression that HNO<SUB>3</SUB> was ionically bonded... Mmmmm...
Anyway, taking a stab i'd say that it would have something to do the solubility, yes, but in realation to the polarity of the substance. Not sure if you have learnt about that so ill give you a very quick run down.

There are 3 types of intermolecular forces, dispersion forces (very weak), dipole forces (weak), and hydrogen bonding (stable) (NOTE: All these intermolecular forces are very weak in realtion to a convential convalent or ionic bond).

These different forms of intermolecular bonding occur due to a substances polarity and a substances polarity is based on the electronegative forces of the atoms that make it up. Now, electronegativity is the 'ability' of an atom to attract an electron.

In a substance such as HCl, Cl (being electronegative) will tend to 'pull' electrons over towards it and there for creating a very slight negative charge (because electrons are negative...). This means one side of the molecule is negatively charged and the other is positively charged. This creates a net dipole, but in other cases this cannot happen-ask teacher in getting tired lol...

Anyway, substances with these charges can bond using one of those 3 intermolecular bonds and join together (This also affected by the substances cohesive and adhesive effects-ask teacher lol...)

As a general rule LIKE DISSOLVES LIKE.

SOOOOOOOOOOOOOOOOOO! Getting back to your question i am still a bit unsure but im betting Na<SUB>2</SUB>CO<SUB>3</SUB> is a polar molecule and the HNO<SUB>3 </SUB>solution does not have a charge (the electrons remain in the 'middle') So when water is added there is a like substance in the solution so that the Na<SUB>2</SUB>CO<SUB>3 </SUB>can dissolve.

That's the best i can do mate. I hope it helps. Let us know of the answer.
Thanks for being so well behaved throughout the lesson .
Cheers!