P = Number of anti-aromatic compound, so the value of x is :

Q = Total number of resonating structures of carbonate ion `[CO_3^(2-)]`
R = Number of alpha-hydrogen in given carbocation
S = Total number of geometrical isomers of `CH_3 – CH=CH-CH=CH_2`
T = Number of compound more acidic then `CH_3CH_2OH`

Sum of (P+Q+R+S+T) - is :

Answer

P = 3, Q = 3, R = 7,S = 2,T = 4 = 19-15 = 4

Explanation

All are more acidic than ethanol `CH_3CH_2OH (pka =16) implies T=4`