Answer : The mass of silver chlorate will be 2.654 grams.
Explanation :
The balanced chemical reaction is,

First we have to calculate the moles of oxygen gas at STP.
As, 22.4 L volume of oxygen gas present in 1 mole of oxygen gas
So, 0.466 L volume of oxygen gas present in
mole of oxygen gas
Now we have to calculate the moles of silver chlorate.
From the balanced chemical reaction, we conclude that
As, 3 moles of oxygen produced from 2 moles of silver chlorate
So, 0.0208 moles of oxygen produced from
moles of silver chlorate
Now we have to calculate the mass of silver chlorate.

Molar mass of silver chlorate = 191.32 g/mole

Therefore, the mass of silver chlorate will be 2.654 grams.