Here, PR=RQ so R is the mid point of PQ.
We know that, the line joining the center of a circle to the mid-point of a chord is perpendicular to the chord.
∴∠R=90∘
Using sum angle property in △OPR
∠P+∠R+∠O=180∘⇒∠P+90∘+25∘=180∘⇒∠P=180∘−90∘−25∘⇒∠P=65∘
PQ=PR+RQ=2+2=4 units