What happens when metal oxide reacts with water?

What type of oxide is aluminium oxide $(Al_2O_3)$?

Which of the following elements will form an acidic oxide?

In the process of electroplating a chromium coating onto an iron spoon,where should the chromium rod be connected?

State whether the following statement is true or false:
Non-metals react with acids to produce a salt and hydrogen gas.

In the refining of silver,the recovery of silver from silver nitrate solution involves displacement by copper metal. Write down the reaction involved.