The solubility rules do not differentiate between Co and Ni, but you should know that 1) all IA metals form salts that are soluble. 2) All chlorides are soluble except Pb, Ag, and Hg chlorides, but gold is particularly inactive, so it does not form the ion easily and is probably insoluble. To find out which of the other two is more soluble, look up the KSP. They have the same KSP equation, so the higher the KSP is, the more soluble the salt.
