A direct current is applied to a solution of CaBr^2, and a gas is evolved from one of the electrodes.
a. Is the gas involved at the anode or the cathode
b. What is the gas?
I am assuming this is an aqueous solution of CaBr2.
Hydrogen gas is evolved at the cathode (the negative electrode) and Br2 is evolved at the anode (the positive electrode).
a. The gas is evolved at the anode.
b. To determine the gas, we need to consider the products of the electrolysis of water. Since water can be present in the solution, it is likely that the gas evolved at the anode is oxygen (O2).
To determine the answers to these questions, we need to understand the process of electrolysis and the products formed at the anode and cathode during electrolysis.
Electrolysis is the process of using an electric current to bring about a chemical reaction in an electrolyte (in this case, the solution of CaBr2).
a. Is the gas evolved at the anode or the cathode?
During electrolysis, positively charged ions (cations) move towards the negative electrode, which is called the cathode, where they gain electrons and are reduced. On the other hand, negatively charged ions (anions) move towards the positive electrode, which is called the anode, where they lose electrons and are oxidized.
Since the question mentions that a gas is evolved, it suggests that the gas is formed at either the anode or the cathode. To determine where the gas is evolved, you need to determine which electrode attracts the anions (negative ions) present in the CaBr2 solution.
In CaBr2, the cations are Ca2+ ions, and the anions are Br- ions. When electricity is applied, the Br- ions (anions) will move towards the anode (positive electrode) and undergo oxidation to form gas.
Therefore, the gas is evolved at the anode.
b. What is the gas?
To determine the gas formed at the anode during electrolysis of CaBr2, we need to consider the oxidation of the Br- ions.
Br- ions are oxidized at the anode (positive electrode) and can form bromine gas (Br2) or other compounds containing bromine, depending on the specific conditions.
So, the gas evolved at the anode is bromine gas (Br2).