Metals and acids

• The typical reaction of a metal and an acid can be summarized as

acid + metal ?→? salt + hydrogen

• For example:

2HCl (aq)?????? +? ????Zn (s)??→??? ZnCl_2?(aq) +?? H₂?(g)

hydrochloric acid + zinc ???→? zinc chloride + hydrogen

• Clearly, the extent of reaction depends on the?reactivity?of the metal and the?strength?of the acid
• Very reactive metals would react dangerously with acids and these reactions are not usually carried out
• Metals low in?reactivity?do not react at all, for instance copper does not react with dilute acids
• Stronger acids?will react?more vigorously?with metals than weak acids. What signs of reaction would be expected to be different between the two?
  • Faster reaction, seen as
    • more effervescence
    • the metal dissolves faster
  • More exothermic

Metals and oxides

• The reaction of an acid with a metal oxide forms two products:

acid + metal oxide?→? salt + water

• For example:

2HCl (aq)? +? ????CaO (s)??? ?→? ? ? ? CaCl₂?(aq)? ????+ ???H₂O (l)

hydrochloric acid + calcium oxide →? calcium chloride + water

Metals and hydroxides

• The reaction with a metal hydroxide and an acid follows the same pattern as an oxide:

acid + metal hydroxide?→? salt + water

• A suitable example might be:

H₂SO_4?(aq) +? Mg(OH)₂?(s)? →? ?? MgSO_4?(aq)? +? ? 2H₂O (l)

sulfuric acid? + magnesium hydroxide →? magnesium sulfate + water

Metals and carbonates

• The reaction between a metal carbonate and an acid produces three products:

acid + metal carbonate?→?salt + water + carbon dioxide

• For example:

2HNO_3?(aq) + CuCO_3?(s)? ?→? ? Cu(NO₃)₂?(aq) + H₂O (l) + CO₂?(g)

nitric acid + copper carbonate?→?copper nitrate + water + carbon dioxide

Metals and hydrogencarbonates

• The reaction between a metal hydrogencarbonate and an acid is the same as the carbonate reaction with a slight difference in stoichiometry:

acid + metal hydrogencarbonate?→?salt + water + carbon dioxide

• An example of this would be:

HCl (aq)? ?+? ? ?NaHCO₃?(s) ????→????NaCl (aq) + H₂O (l) + CO₂?(g)

hydrochloric acid? + sodium hydrogencarbonate? → sodium chloride + water + carbon dioxide

• The acids and bases needed to make different salts can be deduced using the principles covered in the previous section
• The table below summarises these reactions

Making Salts Table

• Note that although some metals can be used to make salts, they are not classified as bases as water is not a product of the reaction

Answer:

The correct option is?D.

• • Metal oxides when reacting with acids produce a salt and water as the only products

轉載自savemyexams