@puneeth
Also see page 7-11. Your concepts will be much clear by reading stalling chapter thoroughly.
Generally sharper the nose , thinner the aerofoil section, the more sudden will be the stall.
Also there are 4 reasons of stall(or seperation)
1)leading edge radius
2)Camber
3)Thickness to chord ratio
4)Chordwise location of maximum thickness and max camber
Transition pt. is the point where airflow changes from laminar to turbulent.
As AOA increases, adverse pressure gradient increases and transition point will move forward.
Statement: 2. Chapter- High Lift Devices> Leading Edge Flaps
"On high speed aerofoil sections the leading edge may have very little camber and have a small radius. This can give flow separation just aft the leading edge at quite low angles of attack"
High speed aerofoils can stall at low aoa (that means when their speed is high). Just imagine if leading edge flaps are not put in those aerofoils, then how will these a/c's slow speed and land at the airport(as they will require high AOA during landing.)