Explain consumer's equilibrium in case of a single commodity with the help of a utility schedule. 

State condition of consumer's equilibrium in case of a single commodity.
Given the market price of a good, how does a consumer decide as to how many units of that good to buy.

Condition of Consumer's Equilibrium (in case of a single commodity).

Consumer's equilibrium is attained when marginal utility of commodity in money terms is equal to its price. Symbolically :

MU_x = P_x

Marginal utility of commodity x is equal to price of x.

A consumer compares price with marginal utility of commodity in terms of money. Since it is difficult to compare MU of a good (expressed in utils) with its price (expressed in र), therefore, MU of a good is first converted in terms of money by dividing MU of a good with MU of a rupee       and then compared, (Mind, MU of a rupee is the extra utility when an extra rupee is spent on other available good, )
The above condition of consumer's equilibrium can be explained with the help of following utility schedule.
Utility Schedule. We know that according to law of diminishing marginal utility, the utility which we draw from each additional unit goes on falling. Let us suppose that a consumer gets marginal utility from consumption of successive oranges as shown in the following utility schedule. Further suppose that price of an orange is र 1 and MU of a rupee is 2 utils. How many oranges will he consume to attain the level of equilibrium (i.e., maximum satisfaction)?

It is clear from the above schedule that initially MU in terms of money is greater than the price of orange. For example from consumption of first orange, the consumer gets utility equal to 10 utils or utility worth र 5 (= 10 ÷ 2) whereas he sacrifices utility of र 1 in the form of price. Thus he gets benefit of र 4(= 5 - 1) from the first orange. So he will buy it. Making such comparisons for successive units he will go on buying additional units till the consumption level of 4th units at which MU in terms of money (i.e., 1) becomes equal to its price (i.e., र 1). Thus at the level of 4 oranges, the consumer reaches the state of equilibrium because the above mentioned condition of equilibrium MU_x = P_x is met here. This condition is sometimes usually described as "marginal utility is equal to price".

The above phenomenon of consumer's equilibrium is graphically shown in the above Fig. 2.2 presuming MU of र (money) to be constant.

Note. Equilibrium equation MU_x = P_x can also be written as   
Clearly a consumer's equilibrium depends upon three factors : (i) MU of a product, (ii) MU of a rupee (money), and (iii) Price of the product.