A buffer is formed by mixing 100 ml of 0.1 m nh4cl with 50 ml of 0.3 m nh3. to this solution 13 ml of 0.1 m naoh is added. what is the approximate ph of the new solution after neutralization? assume a kb of 1.8 × 10−5 for the weak base. 1. 4.62 2. 4.47 3. 9.38 4. 9.45 5. 9.53