Why isn't AddExplosionForce working?

I am trying to get it so that if the block gets hit by the raycast (Executed earlier in the script), It explodes, exploding other blocks too. Sure enough, it goes sailing, but nothing else does. What’s wrong?

if (hit.collider.tag =="Boom"){
				var explosionpos = new Vector3(0,0,0);
				explosionpos = hit.rigidbody.transform.position;
				explosionpos[2] = explosionpos[2] + 5;
				Destroy(hit.collider.gameObject,  2);

You have to apply the explosionforce to all the objects within range of your explosion, not only the box that gets hit by the raycast. Use

Collider colliders = Physics.OverlapSphere(explosionPos, radius);

to find all the colliders within reach and add the explosion force to each one of them.

There is a good example in the documentation: