What is the ph of a neutral solution at a temperature where kw=8.0×10−14?

A neutral solution is when the H⁺ concentration is equal to OH⁻ concentration.
Since there are equal amounts of both H⁺ and OH⁻, solution is neither basic nor acidic, they both react to form water.
kw is the ionic product of water 
kw = [H⁺][OH⁻]
kw = 8.0 x 10⁻¹⁴
since [H⁺]=[OH⁻]
kw =  [H⁺]²
[H⁺]  = √(8x10⁻¹⁴)
[H⁺] = 2.82 x 10⁻⁷ M
pH is calculated using the following equation 
pH = -log [H⁺] 
pH = -log(2.82 x 10⁻⁷ M)
pH = 6.54