▁pro tons . ▁In ▁the ▁Lewis ▁model , ▁a ▁base ▁is ▁an ▁electron ▁pair ▁don or . ▁ ▁Properties ▁General ▁properties ▁of ▁bases ▁include : ▁ ▁Con cent r ated ▁or ▁strong ▁bases ▁are ▁ca ust ic ▁on ▁organ ic ▁matter ▁and ▁react ▁viol ently ▁with ▁acid ic ▁subst ances . ▁A que ous ▁solutions ▁or ▁mol ten ▁bases ▁dis soci ate ▁in ▁ ions ▁and ▁conduct ▁electric ity . ▁Re actions ▁with ▁indic ators : ▁bases ▁turn ▁red ▁lit mus ▁paper ▁blue , ▁phen olph th ale in ▁p ink , ▁keep ▁b rom oth ym ol ▁blue ▁in ▁its ▁natural ▁colour ▁of ▁blue , ▁and ▁turn ▁m eth yl ▁orange - yellow . ▁The ▁p H ▁of ▁a ▁basic ▁solution ▁at ▁standard ▁conditions ▁is ▁greater ▁than ▁seven . ▁B ases ▁are ▁bitter . ▁ ▁Re actions ▁between ▁bases ▁and ▁water ▁ ▁The ▁following ▁reaction ▁represents ▁the ▁general ▁reaction ▁between ▁a ▁base ▁( B ) ▁and ▁water ▁to ▁produce ▁a ▁conjug ate ▁acid ▁( B H +) ▁and ▁a ▁conjug ate ▁base ▁( OH − ): ▁▁ ▁B ( a q ) ▁+ ▁H 2 O ( l ) ▁ <0xE2> <0x87> <0x8C> ▁B H +( a q ) ▁+ ▁O H − ( a q ) ▁ ▁The ▁equilibrium ▁constant , ▁K b , ▁for ▁this ▁reaction ▁can ▁be ▁found ▁using ▁the ▁following ▁general ▁equation : ▁▁ ▁K b ▁= ▁[ B H + ][ OH − ]/ [ B ] ▁ ▁In ▁this ▁equation , ▁the ▁base ▁( B )