Description : (1) the action of ultraviolet rays on oxygen Explanation: The majority of tropospheric ozone formation occurs when nitrogen oxides (NOx), carbon monoxide (CO ) and volatile organic compounds (VOCs), such as xylene, ... violet rays. NOx, CO, and VOCs are called ozone precursors. CO + 2O2 + CO2 + O3
Last Answer : Water is not effective in extinguishing a fire caused by petrol because - (1) the flame is too hot for water to cool it down (2) water and petrol react chemically (3) water and petrol are ... (4) water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn
Description : How is carbon able to form large number of compounds?
Last Answer : Carbon is able to form thousands of compounds because of its unique characteristics like catenation, tetravalency and isomerism
Last Answer : Carbon is able to form thousands of compounds because of its unique characteristics like catenation, tetravalency and isomerism.
Description : Two elements which can form a large number of compounds are (1) Carbon and Hydrogen (2) Carbon and Nitrogen (3) Carbon and Oxygen (4) Carbon and Sulphur
Last Answer : (1) Carbon and Hydrogen Explanation: The carbon-hydrogen bond (C-H bond) is a bond between carbon and hydrogen atoms that can be found in many organic compounds. Compound classes ... bonds are alkanes, alkenes, alkynes, and aromatic hydrocarbons. Collectively they are known as hydrocarbons.
Last Answer : Carbon and Hydrogen
Description : Give reasons for the following observations: (a) The element carbon forms a very large number of compounds. (b) Air holes of a gas burner have to be adjusted when the heated vessels get blackened by the flame. (c) Use of synthetic detergents causes pollution of water. -Chemistry
Last Answer : Answer. (a) Carbon forms large number of compounds since carbon is small in size and can form stable covalent bonds (catenation) and it shows tetravalency. (b) Air holes of gas burner are ... not get blackened. (c) Some synthetic detergents are non-biodegradable, therefore, cause pollution of water.
Description : A molecule is (a) A class of organic compounds (b) The smallest unit of a substance that retains the properties of the substance (c) The spectrum of a substance (d) A small mass
Last Answer : Ans:(b)
Description : Consider following properties of the noble gases. I. They readily form compounds which are colourless. II: They generally do not form ionic compounds.
Last Answer : Consider following properties of the noble gases. I. They readily form compounds which are colourless. II: They ... IV C. I,III,IV D. (D) All
Description : `Na_(2)S_(2)O_(3)` may react with the compounds given in coloum I. `Na_(2)S_(2)O_(3)` exhibits the properties of the type given in the coloum II, matc
Last Answer : `Na_(2)S_(2)O_(3)` may react with the compounds given in coloum I. `Na_(2)S_(2)O_(3)` exhibits the ... "),("d)",I_(2),,"s) an antichlor"):}`
Description : Can List three properties of ionic compounds?
Last Answer : Need answer
Description : Are four physical properties of ionic compounds?
Last Answer : brittlenessmeltinghigh solubility in watervery high boiling points
Description : What are three physical properties of ionic compounds that are associated with ionic bonds and relate them to bond strength?
Last Answer : These are melting point, boiling point, hardness.
Description : What properties may be used to form ionic compounds?
Last Answer : The charateristics properties of ionic compounds include crystal shape,high melting points,and electral conductivity.
Description : Optically active compounds are capable of (A) Different reactions (B) Rotating plane of polarized light (C) Showing same chemical properties (D) None of these
Last Answer : Answer : B
Description : Compounds possessing hormone like properties which have small molecular weight, are termed as : a. Auxins b. Gibberellins c. Kinins d. None of these
Last Answer : Kinins
Description : Washing of coal (A) Reduces its ash & sulphur content (B) Improves its coking properties (C) Increase the fusion point of its ash by removing chlorine compounds (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : For organic compounds, group contribution method can be used for the estimation of (A) Critical properties (B) Specific gravity (C) Specific volume (D) Thermal conductivity
Last Answer : (A) Critical properties
Description : Metalloids (A) Are good conductor of heat & electricity (B) Act as electron donors with metals & as electron acceptor with non metals (C) Are not necessarily solids at room temperature ... & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
Last Answer : D) Are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
Description : (a) Show on a diagram the transfer of electrons between the atoms in the formation of MgO. Write symbols of cation and anion present in MgO. (b) Name the solvent in which ionic compounds are generally soluble. (c) Why are aqueous solutions of ionic compounds able to conduct electricity? -Chemistry
Last Answer : (b) Ionic compounds are soluble in water. (c) It is because aqueous solutions consist of ions which can move freely in them and carry current.
Description : (a) Show the formation of Na2O by the transfer of electrons between the combining atoms. (b) Why are ionic compounds usually hard? (c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state? -Chemistry
Last Answer : (b) It is due to strong force of attraction between oppositely charged ions. (c) In solid state, ions are not free to move whereas in molten state ions are free to move, therefore, they conduct electricity in molten state.
Description : Which of the following compounds are dimerised due to the formation of 3 centre four electron bond-
Last Answer : Which of the following compounds are dimerised due to the formation of 3 centre four electron bond- A. `BH_(3)` B. ... 3)` C. `AIBr_(3)` D. `AlCl_(3)`
Description : Since the enthalpy of elements in their natural state is taken to be zero, the heat of formation `(Delta_(f)H)` of compounds
Last Answer : Since the enthalpy of elements in their natural state is taken to be zero, the heat of formation `( ... C. is zero D. May be positive or negative
Description : Which of the following constituents present in petroleum is responsible for ash formation? (A) Nitrogen compounds (B) Organometallic compounds (C) Sulphur compounds (D) Oxygen compounds
Last Answer : (C) Sulphur compounds
Description : Which of the following reasons are responsible for adoption of post-chlorination of water? 1. Chlorine demand is reduced. 2. Possibility of taste and odour formation is reduced. 3. Possibility of carcinogenic compounds is reduced. 4. Chloramines ... b) 1, 2 & 3 only (c) 1, & 4 only (d) 2, 3 & 4 only
Last Answer : (c) 1, & 4 only
Description : (a) Write electron dot diagram for chlorine (At No. 17) and calcium (At No. 20). Show the formation of calcium chloride by transfer of electrons. (b) Identify the nature of above compound’and explain three physical properties of such compound. -Chemistry
Last Answer : (b) It is ionic compound. Physical properties 1.It is hard and solid. 2.It has high melting and boiling point. 3.It soluble in water.
Description : Two inorganic compounds A and B were heated in a dry test tube. A evolved a colourless gas which turned lead acetate paper black and B evolved a gas w
Last Answer : Two inorganic compounds A and B were heated in a dry test tube. A evolved a colourless gas which turned lead acetate ... ` D. `S^(2-), NO_(3)^(-)`
Description : Assertion: Euro II norms are framed to reduce the content of CO and aromatic compounds from fuels. Reason: These compounds lead to reduced visibility
Last Answer : Assertion: Euro II norms are framed to reduce the content of CO and aromatic compounds from fuels. Reason ... and Reason are false, then mark (4).
Description : Inhalation of lead compounds present in automobile exhaust (using leaded petrol) causes (A) Blood poisoning (B) Anaemia (C) Nervous system disorder (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : Inhalation of lead compounds present in the automobile exhausts (using leaded petrol) causes (A) Blood poisoning (B) Anaemia (C) Nervous system disorder (D) All (A), (B) and (C)
Description : Which of the following compounds is used as an antiknock compound? (a) Ethyllithium (b) Tetraethyllead (c) Ethyl acetate (d) Lead acetate
Last Answer : Tetraethyllead
Description : Which of the following statements best describes a lead compound? a) A compound that contains the element lead b) A compound from the research laboratory that is chosen to go forward for preclinical and ... of a drug. d) The first compound of a structural class of compounds to reach the market.
Last Answer : c) A molecule that shows some activity or property of interest and serves as the starting point for the development of a drug.
Description : Which of the following compounds is ONLY WEAKLY soluble in cold water? w) Silver Nitrate x) Sodium Carbonate y) Sodium Chloride z) Lead Chloride
Last Answer : ANSWER: Z -- LEAD CHLORIDE
Description : Babbitt metals used for making bearings are (A) Tin or lead based alloys (B) Short of antifrictional properties (C) Having homogenous microstructure (D) Yellow metals
Last Answer : (A) Tin or lead based alloys
Description : The greatest number of compounds are formed by the element (a) hydrogen (b) carbon (c) oxygen (d) nitrogen
Description : Carbon forms larger number of compounds because it has
Last Answer : Carbon forms larger number of compounds because it has A. low electron effinity B. variable valency C ... property D. no d-orbital in valency shell
Description : The advantage(s) of using carbon to reduce a number of oxides and other compounds are :
Last Answer : The advantage(s) of using carbon to reduce a number of oxides and other compounds are : A. ... of carbon lowers the melting point of the oxides
Description : Which of the following is false? (1) Most carbon compounds are poor conductors of electricity. (2) The force of attraction between carbon molecules is not very strong. (3) The atomic number of carbon is 6. (4) The earth’s crust has about 2% carbon in the form of minerals.
Last Answer : (4) The earth’s crust has about 2% carbon in the form of minerals.
Description : A large number of organic compounds can be decomposed by (a) Azotobacter (b) Chemolithotrophs (c) Mycoplasma (d) Pseudomonas.
Last Answer : (b) Chemolithotrophs
Description : Which of the following does not lead to formation of new variety ?
Last Answer : Which of the following does not lead to formation of new variety ? A. Somatic hybridisation ... engineering C. Clonal propagation D. UV-radiation
Description : What processes lead directly to the formation of igneous rock?
Last Answer : Melting and solidification!
Description : Exposure of DNA to ultraviolet radiation can lead to the formation of (A) Adenine dimers (B) Guanine dimers (C) Thymine dimers (D) Uracil dimers
Last Answer : Answer : C
Description : When charging lead-acid batteries, the charging rate should be reduced as the battery nears its full charge to ____________. A. prevent damaging battery plates B. allow equalization of cell voltages C. reduce lead sulfate deposits D. increase lead peroxide formation
Last Answer : Answer: A
Description : When charging lead-acid batteries, you should reduce the charging rate as the battery nears its full charge capacity to ______________. A. prevent excessive gassing and overheating B. allow equalization of cell voltages C. reduce lead sulfate deposits D. increase lead peroxide formation
Description : Presence of sulphur in gasoline (A) Leads to corrosion (B) Increases lead susceptibility (C) Decreases gum formation (D) Helps during stabilisatio
Last Answer : (A) Leads to corrosion
Description : Antioxidants are added in petrol to (A) Impart colour to it, for easy identification (B) Minimise the gum formation (C) Prevent icing of the carburettor (D) Prevent the lead build up in engines
Last Answer : (B) Minimise the gum formation
Description : Tetra-ethyl lead is added in gasoline to (A) Increase its smoke point (B) Reduce gum formation (C) Reduce the pour point (D) Increase its octane numbe
Last Answer : (D) Increase its octane numbe
Description : Will dielectric breakdown lead to formation of magnetic monopole? a) Yes b) No
Last Answer : b) No
Description : Salpingitis is associated with_______ and can lead to___________ a. Syphilis; Gumma Formation b. Gonorrhea; Sterility c. Chlamydia; Ophthalmia d. Chancroid; Soft Chancre
Last Answer : b. Gonorrhea; Sterility
Description : Which of the following chemical reactions does not lead to formation of a salt? w) Reaction of salts with acids. x) The reaction of base anhydrides with acid anhydrides. y) Action of water on oxides of nonmetals. z) Reaction of acid with base.
Last Answer : ANSWER: Y -- ACTION OF WATER ON OXIDES OF NONMETALS. (If water reacts with oxides of nonmetals, an acid is formed.)