Which of the following solutions have the same concentration?

Which of the following solutions have the more concentration?

Which of the following solutions have the same molar concentration ?

Which of the following solutions having same concentration will have lowest pH value?

Which out of the following solutions having the same concentration will be most effective in causing the coagulation of the arsenic sulphide sol which is yellowing colour: KCl, MgCl_2, AlCl_3 or Na_3PO_4 ?

Which one of the following solutions with same concentrations is most basic?

Which one of the following solutions with same concentrations will have lowest pH? NaHCO_(3) HCl KOH Na_(2)CO_(3)