Damn, for the buffer solution i got the PH of 6.5 but i rounded it up to 7 and i stated it was neutral.
And for Cr acting both oxidising and reducing agent, i assumed that it was asking for Cr in general and not Cr3+ and that they have to happen simultaneously so i did 4 and 6 i think? The two reactions that have Cr in them since one of those reaction goes oxidation way and the other go towards the reducing way.