Pls help..... questions about acids...?

Question

1. what constituent of acids is responsible for changing the color of litmus paper?

2. what kind of acids, with reference to strength, should be used to displace an acid from its salt?

3. what is the meaning of acid in terms of the ionic theory?

thanks a lot...

Answer 1

Litmus is a weak acid. It has a seriously complicated molecule which we will simplify to HLit. The "H" is the proton which can be given away to something else. The "Lit" is the rest of the weak acid molecule.

There will be an equilibrium established when this acid dissolves in water. :

HLit(Red) <=> H+  + Lit- (Blue)

The un-ionised litmus is red, whereas the ion is blue. If you add an acid to the HLit solution, the excess H+ ions force the equilibrium to move to the left, producing the un-ionised red HLit molecule. The addition of a base causes the dissociation of the HLit molecule, producing the blue Lit-  ion.

  

2.) Strong acids such as H2SO4 are used to displace phosphoric acid from rock phosphate, and HCl from NaCl.

3.) An acid is a substance that donates a proton. (H+ ion)

4) Carbon dioxide.

Na2CO3 + 2HCl → 2NaCl + CO2 + H2O

Answer 2

do ur own bloody homework