At the event horizon of a black hole, the gravitational acceleration is extremely high. In fact, it approaches infinity. The concept of gravitational acceleration as we understand it in classical physics becomes problematic near a black hole's event horizon, where the effects of strong gravitational forces and spacetime curvature are significant.
According to general relativity, which is the current theory of gravity, the curvature of spacetime near a black hole becomes infinitely steep at the event horizon. This means that the gravitational acceleration at the event horizon would require an infinite amount of energy to escape. Consequently, anything that crosses the event horizon, including light, is unable to escape from the gravitational pull of the black hole.
It's important to note that the concept of acceleration near the event horizon is not well-defined in the traditional sense due to the extreme gravitational effects. The escape velocity reaching the speed of light (c) at the event horizon indicates that the gravitational acceleration is exceedingly high but cannot be precisely quantified as a finite value.