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Salts Neutralization and Fertilizers
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Salts Neutralization and Fertilizers
Salts Neutralization and Fertilizers
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1
Question
How can alkaline soil be neutralized?
Answer
By adding acidic fertilizers, such as nitrogen-containing salts (e.g., ammonium salts), to lower the soil pH.
2
Question
Give examples of commonly used antacids.
Answer
Mg(OH)2 (milk of magnesia), Ca(OH)2, and Al(OH)3 are commonly used as antacids.
3
Question
Why are antacids with CO3^2- not used?
Answer
Because they produce CO2 gas, which can cause discomfort due to pressure buildup.
4
Question
How can acidic effluent be neutralized in industrial waste treatment?
Answer
By using Ca(OH)2, Na2CO3, NaOH, or CaO.
5
Question
Why are carbonates preferred over hydroxides in industrial waste treatment?
Answer
a. OH- (aq) is corrosive. b. Adding excess OH- (aq) will redissolve some metal ions.
6
Question
How can alkaline effluent be neutralized?
Answer
By using H2SO4, as it is cheap.
7
Question
What are the three main elements that plants need for growth, which are present in fertilizers?
Answer
Nitrogen (N), Phosphorus (P), and Potassium (K).
8
Question
Give equations for the production of N-containing fertilisers.
Answer
HNO3(aq) + NH3(aq) -> NH4NO3(aq) H2SO4(aq) + 2NH3(aq) -> (NH4)2SO4(aq)
9
Question
How are insect bites neutralized?
Answer
By using an alkaline solution, such as NaHCO3.
10
Question
Define a salt.
Answer
Ionic compounds formed when one or more ionizable hydrogen atoms in an acid are replaced by metal ions or ammonium ions.
11
Question
Define a normal salt.
Answer
A salt where all ionizable hydrogen atoms have been replaced by NH4 ions or metal ions (complete neutralization).
12
Question
Define an acid salt.
Answer
A salt where only some of the ionizable hydrogen atoms have been replaced (incomplete ionization); the salt still contains ionizable hydrogen atoms.
13
Question
What types of acids can form acid salts?
Answer
Polybasic acids only.
14
Question
Are acid salts formed from strong acid/strong alkali acidic or alkaline?
Answer
Acidic.
15
Question
Are acid salts formed from weak acid/strong alkali acidic or alkaline?
Answer
Alkaline.
16
Question
How are salts named?
Answer
Cation + Anion (e.g., NaCl - Sodium Chloride). For acid salts, add 'hydrogen' before the anion name (e.g., KHSO4 - Potassium Hydrogensulphate). Indicate the number of water of crystallization (e.g., CuSO4·5H2O - Copper(II) sulphate-5-water).
17
Question
Describe the steps for preparing insoluble salts.
Answer
1. Dissolve the two solids used in water separately. 2. Mix the two solutions and stir thoroughly. 3. Filter out the precipitate (insoluble salt). 4. Wash the precipitate with distilled water. 5. Dry the precipitate.
18
Question
What is the purpose of pressing crystals between filter papers after filtering them?
Answer
To dry the crystals and obtain a hydrated salt.
19
Question
Why is excess metal, insoluble base, or insoluble carbonate used when preparing soluble salts of metals other than K, Na, NH4?
Answer
The unreacted metal/base/carbonate is in solid form and can be easily removed by filtration, ensuring that there is no excess acid in the final solution.
20
Question
Why is it important to use an exact mole ratio when preparing soluble salts of K, Na, or NH4?
Answer
All K, Na, and NH4 ionic compounds are soluble in water, so any excess will dissolve and cannot be removed by filtration, resulting in an impure product.
21
Question
What type of salt is formed when crystals are dried in an oven?
Answer
An anhydrous salt.
22
Question
What is the first step in preparing soluble salts of K, Na, or NH4?
Answer
Titration to determine the exact volume of acid needed to neutralize the KOH/NaOH/NH3.
23
Question
After filtration of the product mixture, what is the next step in creating crystals?
Answer
Heat the filtrate to remove most of the water to concentrate it into a saturated solution of the soluble salt.
24
Question
Why is the filtrate cooled slowly?
Answer
To form large crystals of the soluble salt.
25
Question
What is used to wash the crystals after filtering them out of the solution?
Answer
A small amount of cold distilled water.
26
Question
What term describes a salt losing its water of crystallization upon exposure to air?
Answer
Efflorescent
27
Question
A crystalline compound containing water molecules is called what?
Answer
Hydrate
28
Question
What term describes a substance that contains no water?
Answer
Anhydrous
29
Question
What is the process called when a substance absorbs moisture from the air until it dissolves in the absorbed water and forms a solution?
Answer
Deliquescence
30
Question
What is the property of a substance that absorbs moisture from the air but does not dissolve called?
Answer
Hygroscopic