Which of the following is a thermosetting plastic? (a) PVC (b) Teflon (c) Bakelite (d) Nylon
Answer: (c) Bakelite Bakelite is a thermosetting plastic.
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Which of the following is not a correct statement about the trends when going from left to right across the periods of periodic table? (A) The elements become less metallic in nature. (B) The number of valence electrons increases. (C) The atoms lose their electrons more easily. (D) The oxides become more acidic.
Answer:(C ) The atoms lost their electrons more easily
Which one of these is a monomer of bakelite? (A) Vinyl acetate (B) Tetrafluoroethylene (C) Propylene (D) Formaldehyde
Answer: (D) Formaldehyde
Many salts absorb water from the atmosphere. This property is called: (A) Hydration (B) Dehydration (C) Efflorescence (D) Deliquescence.
Answer: (D) Deliquescence
Calculate the number of moles present in 9 g of ethane.
Mass of ethane = 9 g Molar mass of ethane C2H6 = 30 g mol-1 No. of moles = Mass/... View Article
What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds (i) Are Poor conductors of electricity and (ii) Have low melting and boiling points? What happens when this compound burns in oxygen?
Methane is a colorless, odourless and highly flammable gas which is the main component of natural gas.The electron dot structure... View Article
What are Etard Reaction and Gattermann Koch Reaction? Give example
Etard Reaction Mechanism offers a way to oxidize aromatic methyl groups. It has named to honour the French scientist Alexandre... View Article
Define Valency and Variable Valency with examples
Valency is the combining capacity of element. The number of elements donated or accepted by an atom of an element... View Article
Draw the electron dot structure of ethene, C2H4.
C2H4 is the simplest alkene with the chemical name Ethylene or Ethene. It is also called Polyethylene or Etileno. It is commonly used... View Article
Give three advantages of polythene over natural materials ?
The advantages of polythene over natural materials are: They are water-resistant Flexible and durable Versatile and can be tailored to meet... View Article
Which has the least energetic molecules and why? (A) Solids (B) Liquids (C) Gases (D) Pasmas.
Answer: (A) Solids Solids are incompressible, meaning the constituent particle is arranged close to each other and because of that,... View Article
Solid CO2 is an example of which crystal?
Solid CO2 is an example of molecular crystal. They have relatively weak intermolecular binding.
Increasing order of electron gain enthalpy of group 16 is:
Increasing order of electron gain enthalpy of group 16 is: O < S < Se < Te As the size... View Article
Write electron dot structure of calcium and sulphur.
Electron dot structure of Calcium: 2, 8, 8, 2 Electron dot structure of Sulphur: 2, 8, 6
Henrys law constant for CO2 in water is 167 times 10^8 pa at 298K. Calculate the quantity in 500 mL of soda water when packed under 2.5 atm pressure at 298 K.
KH = 1.67 x 108 Pa pCO2 = 2.5atm = 2.5 × 101325 Pa By Henry’s Law: P=KH × x x = (2.5×1.013×105)/(1.67 × 108) = 1.517... View Article
The animal without skull is (a) Acrania (b) Acephalia(c) Apteria (d) Acoelomate
Answer: (a) Acrania The animal without a skull is called Acrania.
Mention any two components of blood?
The main components of blood are: Red blood cells (RBC) White blood cells (WBC) Plasma Platelets Learn in brief: Components... View Article
A speech on ‘Global Warming’ for ASL of about 1 min
Global warming is the continuous heating of the earth’s atmosphere due to the green house effect. Due to the global... View Article
What is the nature of cell walls in diatoms?
The cell walls (frustules) of diatoms form two thin overlapping cells. It is made up of silica.
Modern farming method require a great deal of _______
Modern farming method requires a great deal of capital such that farmer now, needs more money than before. These modern... View Article
