Will of inherited property

As per Hindu Law, the person who inherits the property from his ancestors cannot give away the property to someone else by making a will as the next generations have equal rights on that property. If an individual wants to make a will for self acquired property, that is completely legal. The laws are applicable differently as per the conditions stated by Indian Succession Act, as in the case of Christians, Parsis and others.

Maybe, I couldn't express myself clearly, so to paraphrase: The inheritance is not from ancestors but deceased spouse.

Laws differ in personal laws of the testator i.e., different laws govern Hindus, Muslims, Christians and others, what is the state in your case ?

Intestate property devolved upon widow from her deceased husband shall form part of her self-acquired and not inherited.

The topic / subject of your query includes deeper legal issues, it is appropriate to consult a local prudent lawyer with relevant records. 

Thank you, Sirs.

Presuming it to be an intestate succession,  the property becomes her own and absolute property, that is her self acquired property. 

This means she's at liberty to transfer her property to any one of her choice by any mode including the proposed testamentary disposition through a Will.