Can clapping be invalid? Is there a need for necessary form and matter for clapping to be valid? It looks and sounds like clapping but isn’t really?
I think you are referring to
liceity, but Canon Law does not strictly govern applause, so perhaps the more appropriate term is
propriety.
As our Pope Emeritus said when he was Cardinal Ratzinger,
Wherever applause breaks out in the liturgy because of some human achievement, it is a sure sign that the essence of liturgy has totally disappeared and been replaced by a kind of religious entertainment.
- Spirit of the Liturgy
However, that does not preclude the use of applause to celebrate God’s works. Therefore, intention is everything here. If the congregation clapped for the choir after they finished the song, then it may be clapping for their singing, which is a human achievement and detracts from the Mass’s central focus on God.
However, if - as you say - the congregation were clapping at the moment of conclusion of the Mass along with the recessional song, they may be using their applause as a joyous celebration of the resurrection of Christ. Perhaps it is better for us to give the benefit of the doubt here.
That being said, I like to be conservative on the use of clapping. The only time I would tolerate applause is at a baptism, confirmation, ordination, installation or wedding. That’s a lot of possible use cases, but I would certainly not clap because of a song.
