Answer:
At anode - 
At cathode - 
Explanation:
Electrolysis of NaBr:
Water will exist as:

The salt, NaBr will dissociate as:

At the anode, oxidation takes place, as shown below.

At the cathode, reduction takes place, as shown below.

The answer to this question will be C
Answer:
13.20 cm/s is the rate at which the water level is rising when the water level is 4 cm.
Explanation:
Length of the base = l
Width of the base = w
Height of the pyramid = h
Volume of the pyramid = 
We have:
Rate at which water is filled in cube = 
Square based pyramid:
l = 6 cm, w = 6 cm, h = 13 cm
Volume of the square based pyramid = V





Differentiating V with respect to dt:




Putting, h = 4 cm


13.20 cm/s is the rate at which the water level is rising when the water level is 4 cm.