Lesson 16 Applied Chemistry
In this post titled “9th Science Guide – Applied Chemistry,” various topics related to applied chemistry are covered. The post includes multiple-choice questions, fill in the blanks, matching exercises, and questions requiring brief and detailed answers.
Applied Chemistry Book Back Answer
I. Choose the correct answer:
1. One Nanometre is
- 10-7 metre
- 10-8 metre
- 10-6 metre
- 10-9metre
Ans: 10-9 metre
2. The antibiotic Penicillin is obtained from _________
- plant
- microorganism
- animal
- sunlight
Ans: microorganism
3. 1% solution of Iodoform is used as
- antipyretic
- antimalarial
- antiseptic
- antacid
Ans: antiseptic
4. The cathode of an electrochemical reaction involves ___________
- oxidation
- reduction
- neutralisation
- catenation
Ans: catenation
5. The age of a dead animal can be determined by using an isotope of ________
- carbon
- iodine
- phosphorous
- oxygen
Ans: carbon
6. Which of the following does not contain natural dyes?
- Potato
- Beetroot
- Carrot
- Turmeric
Ans: Potato
7. This type of food protects us from deficiency diseases.
- Carbohydrates
- Vitamins
- Proteins
- Fats
Ans: Vitamins
8. Radiochemistry deals with
- oxidants
- batteries
- isotopes
- nanoparticles
Ans: isotopes
9. The groups responsible for the colour of an organic compound is called
- isotopes
- auxochrome
- chromogen
- chromophore
Ans: auxochrome
10. Chlorinated hydrocarbons are used as
- fertilizers
- pesticides
- food colourants
- preservatives
Ans: pesticides
II. Fill in the blanks.
1. _________ is an electrochemical cell which converts electrical energy into chemical change (Reaction).
Ans: Electrolytic cell
2. Painkiller drugs are called __________
Ans: Analgesics
3. Indigo is a ___________ dye.
Ans: Antipyretics
4. ________, ________ and _________ are macronutrients required for plant growth.
Ans: Nitrogen, Phosphorous, potassium
5. __________ is a chemical used in fingerprint analysis.
Ans: Ninhydrin
6. Aspirin is an ___________
Ans: Antipyretics
III. Match the following.
| 1. Antipyretics | Large surface area | ||
| 2. Corrosion prevention | Iodine-131 | ||
| 3. Hyperthyroidism | Fever | ||
| 4. Nanoparticle | Cancer cell identification | ||
| 5. Nanorobotics | Electroplating | ||
| Ans : 1 – C, 2 – E, 3 – B, 4 – A, 5 – D | |||
IV. Answer in brief.
1. What is Radio Carbon Dating?
Radio Carbon Dating is a method by which the age of fossil wood or animal is determined using C-14 isotope.
2. What are called Anaesthetics? How are they classified?
The drugs which cause loss of sensation are called Anaesthetics.
Types of Anaesthetics:
- General anaesthetics
- Local anaesthetics
3. What is the need for chemical fertilizers in crop fields?
Fertilizers are chemical compounds added to crop fi eld for supplying essential micro and macro nutrients required for crop growth.Depending on the nature of soil, these fertilizers are used singly or as mixtures
4. What is Forensic chemistry related to?
In general, forensic chemists work in four steps in the investigation of crime.
- Collection of Evidences
- Analysis of evidences
- Collaboration
- Report of findings
6. What is Chemotherapy?
Treatment of certain diseases by destroying the invading organism without damaging the cells of the host, by the use of certain organic compounds is known as Chemotherapy. It is widely used for treating cancer
V. Answer in Detail
1. Explain the types of dyes based on their method of application.
Acid dyes:
These are acidic in nature and used for dyeing animal fibres and synthetic fibres. These can be used for protein fibres such as wool and silk.
E.g. Picric acid, Naphthol yellow-s
Basic dyes:
These are basic dyes containing basic groups (-NH2,- NHR, – NR2). They are used for dyeing animal fibres and plant fibres.
Mordant dyes or Indirect dyes:
These dyes have a poor affinity for cotton fabrics and hence do not dye directly. They require pretreatment of the fibre with a mordant. Mordant (latin : mordere = to bite) is a substance which can be fixed to the fibre and then can be combined with the dye to form an insoluble complex called lake. Aluminium, chromium, and iron salts are widely used as mordants.
E.g. alizarin.
Direct dyes:
They have high affinity for cotton, rayon and other cellulose fibre. So they are applied directly as they fix firmly on the fabric.
E.g. Congo red
Vat dyes :
It can be used only on cotton and, not on silk and wool. This dyeing is a continuous process and is carried out in a large vessel called vat. So it is called as vat dye.
E.g. Indigo
2. Name various food additives and explain their functions.
| Type of additive | Function of the additive | Example |
| Preservatives | They protect food from spoilage by microorganism in storage. | Vinegar, Sodium benzoate, benzoic acid, sodium nitrite |
| Colourants | They give pleasant colours to food | Carotenoids, Anthocyanin, Curcumin |
| Artificial Sweeteners | They add sweet taste to food | Saccharin, Cyclamate |
| Flavor enhancers | They are used to enhance the flavour of food items | Monosodium glutamate, Calcium diglutamate |
| Antioxidants | They prevent the oxidation of food. They protect us against cardiovascular disease. | Vitamin C, Vitamin E, Carotene |
3. Draw the cell diagram of Daniel cell. Give its reactions.
It is a type of galvanic cell in which zinc metal acts as an anode and copper metal as a cathode. Aqueous zinc sulphate solution makes the anodic electrolyte whereas aqueous copper sulphate solution makes the cathodic electrolyte. Saturated solution of potassium chloride (KCl) acts as a salt bridge. The following figure depicts the construction of Daniel cell.
At anode, zinc undergoes oxidation losing its electrons.
Zn(s) → Zn2+ + 2e– (Oxidation)
At cathode, copper ions from cathodic electrolyte gain electrons at the surface of cathode and get reduced to copper metal.
Cu2+ + 2e– → Cu(s) (Reduction)
Net reaction: Zn(s) + Cu2+ → Zn2+ + Cu(s)
Cell potential of Daniel cell is 1.1 V
VI. Higher Order Thinking Skills.
1. Batteries that are used in mobile phones can be recharged. Likewise, can you recharge the batteries used in watches? Justify your answer.
A watch battery is a primary cell, that is designed to be used once, and discarded, and hence it is not rechargeable.
2. Sudha met with a fire accident. What kind of drug(s), she must take?
Neosporin, Bacitracin, and Silvadene are used for the treatment of fire accidents.
3. The soil pH of cropland is 5. What kind of fertilizers should be used on that land?
The soil pH of cropland is 5. it is the relative acidity of the soil, so we use the alkaline lime fertilizer on that land.