Answer:
of HA is 6.80
Explanation:
Acid dissociation constant (
) of HA is represented as-
![K_{a}=\frac{[H^{+}][A^{-}]}{[HA]}](https://tex.z-dn.net/?f=K_%7Ba%7D%3D%5Cfrac%7B%5BH%5E%7B%2B%7D%5D%5BA%5E%7B-%7D%5D%7D%7B%5BHA%5D%7D)
Where species inside third bracket represents equilibrium concentrations
Now, plug in all the given equilibrium concentration into above equation-
So, 
Hence 
Answer:
2.5×10^-7mol/dm^3
Explanation:
Firstly convert the cm^3 to dm^3
200×1000=200000dm^3
Calculate the g/dm^3
2/200000=0.00001g/dm^3
To calculate mol/dm^3
Mol/dm^3=mass given\molar mass
=0.00001/40
=2.5×10^-7mol/dm^3
Due to it's electronic configuration w/c is 1s2 2s2 2ps 3s1 considering the last w/c is 3s1, sodium should be in row 3 period a1.
