In the play, John Proctor's hanging is not shown. Consider this scene in the film, and the recital of the 10 commandments. What is the effect of this scene?

The effect of the hanging scene is to give closure at the end of the film and it is part of the dramatic effect the film builds by adding a number of different scenes not originally in the play, like the jail scene between John Proctor and Abigail Williams.

Explanation:

The effect of reciting the 10 commandments and forgetting the commandment against adultery is ironic because John Proctor committed adultery with Abigail Williams and it is Elizabeth Proctor who reminds him of the sixth commandment. But the hanging scene in the movie has John Proctor and the others condemned to hang and on the gallows reciting the Lord's Prayer. John is hung just before he can finish it. The scene in the film creates a sense of sadness and also the serious consequences of Abigail Williams's actions and false accusations.