$$
begin{align*}
n_1 = n_{air} &= 1 \
theta_1 &= 43 text{textdegree} \
theta_2 &= 27 text{textdegree}
end{align*}
$$

The index of refraction for the benzene at angle $27 text{textdegree}$ with the normal can be calculated by applying Snell’s Law :

$$
begin{align*}
n_1 sin theta_1 &= n_2 sin theta_2 \
n_2 &= dfrac{n_1 sin theta_1}{sin theta_2} \
&= dfrac{1 (sin 43 text{textdegree})}{sin 27 text{textdegree}}
end{align*}
$$

$$
{boxed{n_2 = 1.5022}}
$$