Valency Determination of Compounds with Different Valences
Determining the valency of a compound formed by two reactants with different valences involves understanding the concept of valency and balancing the charges of the ions involved. Here is a detailed explanation of how the valency of such compounds is determined:

Understanding Valency:
Valency is the combining capacity of an element to form compounds. It is determined by the number of electrons an atom gains, loses, or shares to achieve a stable electron configuration.

Balance the Charges:
When two reactants with different valences combine to form a compound, the charges must balance out. For example, if one reactant has a valence of +2 and the other has a valence of -3, the compound should have a total charge of zero.

Using Cross-Over Method:
One method to determine the valency of the compound is the cross-over method. In this method, the valences of the two elements are crossed over and used as subscripts in the formula of the compound.

Example:
Let's consider the reaction between calcium (Ca) with a valency of +2 and chlorine (Cl) with a valency of -1. The compound formed will be CaCl2. Here, the valency of calcium is crossed over to become the subscript of chlorine, resulting in a neutral compound.

Overall Charge Neutrality:
It is essential to ensure that the compound formed has an overall charge of zero. This means that the positive and negative charges should balance each other out to maintain electrical neutrality.
By following these steps and principles, one can determine the valency of a compound formed by reactants with different valences accurately.