盐族是什么意思？
我们对现代化学中的酸和碱（也称为碱）有很好的了解。酸和碱被用作实验室试剂、工业催化剂、烹饪添加剂和清洁产品，它们渗透到我们从实验室到厨房的生活中。然而，化学家花了几个世纪的时间才在历史进程中完全理解这些化学物质。
什么是盐？
Salts are ionic substances that are formed when an acid and a base react to neutralise each other. Salts have no electrical charge.
还有许多其他类型的盐，但氯化钠是最普遍的。食盐或食盐都是氯化钠的术语。氯化钠用于使膳食味道更好。
盐的特点是：
- 大多数盐在性质上是结晶的。
- 可以使用透明或不透明的盐。
- 大多数盐是水溶性的。
- 在熔融状态下，盐溶液也可以传输电力。
- 盐的味道可以是咸的、酸的、甜的、苦的或鲜味（咸味）。
- 中性盐没有气味。
- 有无色或有色盐可供选择。
盐的性质是：
分子中的氯化钠表现出与元素钠和氯有很大不同的特性。
- 盐水是良好的电导体，因为它含有离子。
- 离子通过静电引力结合在一起，并在它们之间形成化学连接。
盐的种类
- 酸式盐- 酸式盐是通过部分中和二质子或多元酸而产生的盐。这些盐含有一种可以电离的离子，以及另一种阳离子。阴离子主要由可电离的 H+ 组成。在烘焙中，使用了某些酸式盐。例如 NaHSO 4 、KH 2 PO 4等。
- 碱性或碱盐- 碱性盐是当强碱被弱酸部分中和时产生的盐。它们在水解时分解成碱性溶液。这是因为当碱式盐水解时，溶液中会产生弱酸的共轭碱。例如白铅（2PbCO 3 ·Pb(OH) 2 ）等。
- 复盐-复盐是其中含有一种以上阳离子或阴离子的盐。它们是通过结合两种不同的盐制成的，这些盐在相同的离子晶格中结晶。例如，酒石酸钾钠 (KNaC 4 H 4 O 6 .4H 2 O) 也称为罗谢尔盐。
- 混合盐 - 混合盐是由两种盐的预定混合物组成的盐，这两种盐通常共享一个共同的阳离子或阴离子。例如。 CaOCl 2 .
盐的水解：盐与水的反应称为盐水解。中和反应是该反应的逆反应。在此过程中盐与水反应时会生成酸和碱成分。盐在水解过程中解离成离子，完全或部分取决于盐的溶解度积。
盐家族
Salts with similar acidic or basic radicals are classified as belonging to the same family.
例如：
- 氯化物家族包括氯化钠 (NaCl) 和氯化钙 (CaCl 2 )。
- 钙家族包括氯化钙 (CaCl 2 ) 和硫酸钙 (CaSO 4 )。
- 锌家族包括氯化锌 (ZnCl 2 ) 和硫酸锌 (ZnSO 4 )。
中性、酸性和碱性盐
1. 中性盐
在自然界中，由强酸和强碱相互作用形成的盐是中性的。这种盐的pH值为7，被认为是中性的。氯化钠、硫酸钠和氯化钾。
For example:
- Sodium chloride (NaCl): It is created when hydrochloric acid (a powerful acid) reacts with sodium hydroxide (a strong base).
NaOH + HCl → NaCl + H2O
- Sodium Sulphate (Na2SO4): It is created when sodium hydroxide (a strong basic) reacts with sulphuric acid ( a strong acid).
2NaOH + H2SO4 → Na2SO4 + 2H2O
- Potassium Chloride (KCl): It is created when potassium hydroxide (a strong base) reacts with hydrochloric acid (a strong acid).
KOH + HCl → KCl + H2O
2.酸性盐
酸性盐是由强酸和弱碱反应产生的盐。酸性盐的 pH 值小于 7。例如硫酸铵、氯化铵和其他铵化合物。
For example:
- Ammonium chloride: Hydrochloric acid (a powerful acid) reacts with ammonium hydroxide to produce ammonium chloride (a weak base).
NH4OH + HCl → NH4Cl + H2O
- Ammonium sulphate: After a reaction between ammonium hydroxide (a weak base) and sulphuric acid, ammonium sulphate is produced (a strong acid).
2NH4OH + H2SO4 → (NH4)2SO4 + 2H2O
3. 碱性盐
碱性盐是由弱酸和强碱反应产生的盐。碳酸钠、乙酸钠和其他盐是例子。
For example:
- Sodium carbonate: The interaction between sodium hydroxide (a strong base) and carbonic acid produces sodium carbonate (a weak acid)
H2CO3 + 2NaOH → Na2CO3 + H2O
- Sodium acetate: After a reaction between a strong base, sodium hydroxide (a strong base), and acetic acid, sodium acetate is produced (a weak acid)
CH3COOH + NaOH → CH3COONa + H2O
形成酸性、碱性和中性盐的原因：
- 当强酸与弱碱结合时，碱不能完全中和酸。结果，形成酸式盐。
- 当与弱酸结合时，酸不能完全中和强碱。结果，生成碱式盐。
- 当等强度的酸和碱反应时，它们会完全相互中和。这导致形成中性盐。
盐的pH值
- 中性盐的 pH 值几乎等于 7。
- 酸性盐的 pH 值小于 7。
- 碱性盐是一种 pH 值大于 7 的盐。
示例问题
问题1：当口腔的pH值低于5.5时，为什么会开始蛀牙？
解决方案：
When the pH of our mouth falls below 5.5, tooth decay begins. This is because below this pH value, the mouth’s medium becomes more acidic, causing tooth enamel to deteriorate more quickly.
问题2：鲜奶的pH值为6，转化为凝乳（酸奶）时，pH值会升高还是降低？为什么？
解决方案：
The pH of milk decreases as it turns into curd (yoghurt). This is because lactic acid is formed during the curd’s production, making it sour.
问题3：中和的定义是什么？
解决方案：
Neutralisation is the reaction between an acid and a base. Salt and water are generated as a result of the growth of heat in this process.
Acid + Base ➝ Salt + Water + (heat is evolved)
For example:
HCl + NaOH ➝ NaCl + H2O
问题4：中和反应的实际应用是什么？
解决方案：
Neutralization aids us in a variety of ways in our daily lives. The following are some of the applications:
- When we have acid reflux, we take an antacid to help us feel better. An antacid counteracts the effects of too much acid.
- When an ant bites, a moist baking soda or calamine solution is applied on the skin to neutralise the action of the acid injected into the skin.
- Plants do not grow well in soil that is either excessively acidic or too basic. When the soil is excessively acidic, it is treated with bases such as quick lime or slaked lime, and when it is too basic, it is amended with organic matter. Organic stuff produces acids, which balance out the soil’s basic nature.
- Factory wastes: Factory wastes contain acids, which are toxic to aquatic life. Basic compounds are added to these wastes to neutralise them.
问题 5：写出盐的性质。
解决方案：
Properties of salts are:
- Saltwater is a good conductor of electricity because it contains ions.
- The ions are held together by electrostatic attraction, and a chemical connection is formed between them.
问题 6：写出盐的特征。
解决方案：
Following are the characteristics of salts:
- The majority of the salts are crystalline in nature.
- Transparent or opaque salts are available.
- The majority of salts are water soluble.
- In their molten condition, salt solutions transmit electricity as well.
- Salt can be salty, sour, sweet, bitter, or umami in flavour (savoury).
- Neutral salts have no odour.
- Colorless or coloured salts are available.
问题7：盐酸与氢氧化铵反应会发生什么？
解决方案：
Hydrochloric acid (a powerful acid) reacts with ammonium hydroxide to produce ammonium chloride (a weak base).
The reaction is :
NH4OH + HCl → NH4Cl + H2O