11) Br2 + NaF  F2 + NaBr

12) HOH + PbCl2 Pb(OH)2 + HCl

13) KBr + Al2(SO4)3  AlBr3 + K2SO4

14) C2H6 + O2  CO2 + H2O

15) CaCl2+ Na3PO4  Ca3(PO4)2 + NaCl

16) Be + Cl2  BeCl2

17) HCl + Ga  GaCl3 + H2

18) F2 + N2  NF3

19) CaO + Li2Se  CaSe2 + Li2O

20) NaCl + H2SO4  NaSO4 + HCl
please solve as many as you can

Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.