Answer:
The index of refraction of the liquid is 1.35.
Step-by-step explanation:
It is given that,
Critical angle for a certain air-liquid surface,

Let n₁ is the refractive index of liquid and n₂ is the refractive index of air, n₂ =1
Using Snell's law for air liquid interface as :




So, the index of refraction of the liquid is 1.35. Hence, this is the required solution.