acids and bases

• The pH scale runs from below 0 to above 14
• A neutral solution has equal concentrations of H+ and OH- ions
• An acidic solution has a higher concentration of H+ ions that OH- ions
• An alkaline solution has a higher concentration of OH- ions than H+ ions
• dilution of an acidic solution will increase pH towards 7
• dilution of an alkaline solution will decrease pH towards 7
• metal oxide + water = metal hydroxide
• an insoluble substance will have no effect on pH