State one physical property that cobalt and potassium have in common.
State one physical property for which cobalt and potassium have different values.
Describe how the physical property given in (b)(i) differs for cobalt and potassium.
Give two further observations that would be seen when a small piece of potassium is added to cold water.
Describe how to test for hydrogen. test result
State one other method that would increase the rate of reaction.
Use collision theory to explain why heating the dilute hydrochloric acid increases the rate of reaction.
A student adds water to a blue solution containing $[\text{CoCl}_4]^{2-}$ ions. Describe the observation made by the student. Give a reason using the position of the equilibrium.
Another student cools a blue solution containing $[\text{CoCl}_4]^{2-}$. The blue solution turns pink. What does this information indicate about the forward reaction?
Deduce the charge on the cobalt ion present in Co(OH)$_3$.