Which of the following statements about bentonite are CORRECT
(P) Gycerin is used to pre-wet the bentonite prior to mixing with water to form its gel
(Q) Aqueous bentonite suspensions retain their viscosity above pH 6 but are precipitated by acids
(R) MgO increase gel formation while alcohol in significant amounts can precipitate bentonite gel
(S) Betonite exhibits rheopexy