Which of the following elements has the atomic number greater than that of Phosphorus? (1) Aluminium (2) Silicon (3) Chlorine (4) Magnesium

1 Answer

Answer :

(3) Chlorine Explanation: Chlorine is a chemical element with symbol Cl and atomic number 17. Phosphorus is a chemical element with symbol P and atomic number 15.

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Description : Which one of the following elements is least likely to be found in commercial fertilisers? (1) Nitrogen (2) Phosphorus (3) Potassium (4) Silicon

Last Answer : (4) Silicon Explanation: Commercial Fertilizers - a substance containing one or more recognized plant nutrients and that is used for its plant nutrient content or that is designated for use or claimed to have value in promoting plant growth.

Description : Which of the following groups of elements have an OUTER ELECTRONIC configuration of S-2-P-2? w) halogens x) Nitrogen-Phosphorus Group y) Carbon-Silicon Group z) Boron-Aluminum Group

Last Answer : ANSWER: Y -- CARBON-SILICON GROUP

Description : Of the nonmetallic elements the one least likely to be found in organic compounds is: w) nitrogen x) phosphorus y) chlorine z) selenium

Last Answer : ANSWER: Z -- SELENIUM

Description : Which of the following material of construction may be recommended by a chemical engineer for handling a gaseous chlorine (dry or wet) stream in a fluid flow system? (A) High silicon iron, silicon rubber ... Mild steel and stainless steel (C) Cast iron, tin and aluminium (D) Copper, nickel and Monel

Last Answer : (A) High silicon iron, silicon rubber, Kel-F and Teflon

Description : An atomic clock is based on transitions in - (1) Sodium (2) Caesium (3) Magnesium (4) Aluminium

Last Answer : (2) Caesium Explanation: An atomic clock is a clock device that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms ... the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS.

Description : An atomic clock is based on transitions in (1) Sodium (2) Caesium (3) Magnesium (4) Aluminium

Last Answer : Caesium

Description : Which of the 3rd period elements loses electrons most readily? w) Sodium x) Magnesium y) Aluminum z) Silicon

Last Answer : ANSWER: A-SODIUM

Description : The elements known as primary nutrients for plants (1) Nitrogen, Phosphorus and Potassium (2) Nitrogen, Oxygen and Silicon (3) Potassium, Boron and Nitrogen (4) Nitrogen, Phosphorus and Iron

Last Answer : (1) Nitrogen, Phosphorus and Potassium Explanation: Nitrogen (N), Phosphorus (P) and Potassium (K) are considered as the three essential or primary nutrients for plants. Together they make up ... need small quantities of iron, manganese, zinc, copper, boron and molybdenum, known as trace elements

Description : The elements known as primary nutrients for plants (1) Nitrogen, Phosphorus and Potassium (2) Nitrogen, Oxygen and Silicon (3) Potassium, Boron and Nitrogen (4) Nitrogen, Phosphorus and Iron

Last Answer : Nitrogen, Phosphorus and Potassium

Description : Which of the following elements is a constituent of biotin? (a) Magnesium (b) Calcium (c) Phosphorus (d) Sulphur

Last Answer : (d) Sulphur

Description : About 98 percent of the mass of every living organism is composed of just six elements including carbon, hydrogen, nitrogen, oxygen and (a) sulphur and magnesium (b) magnesium and sodium (c) calcium and phosphorus (d) phosphorus and sulphur.

Last Answer : (d) phosphorus and sulphur.

Description : Compared to Chlorine, Bromine has: w) smaller atomic size x) higher density y) lower boiling point z) greater number of outer electrons

Last Answer : ANSWER: X -- HIGHER DENSITY

Description : Which of the following elements is found in the earth's crust as both a native element and as a compound? w) argon x) copper y) chlorine z) silicon

Last Answer : ANSWER: X -- COPPER

Description : The oxygen evolved during photosynthesis, comes from water molecules. Which one of the following pairs of elements is involved in this reaction? (a) Magnesium and Molybdenum (b) Magnesium and Chlorine (c) Manganese and Chlorine (d) Manganese and Potassium

Last Answer : (c) Manganese and Chlorine

Description : Give reason: Atomic size of sodium atom is greater than that of chlorine atom.

Last Answer : Sodium is in the 1 st group where as chlorine is in 17 th group. We know that the atomic size decreases down the group. Hence sodium atom has larger atomic size than that of chlorine atom.

Description : The element used for vulcanizing rubber is - (1) Sulphur (2) Bromine (3) Silicon (4) Phosphorus

Last Answer : (1) Sulphur Explanation: The vulcanization of neoprene or polychloroprene rubber (CR rubber) is carried out using metal oxides (specifically MgO and ZnO, sometimes Pb3O4) rather than sulfur compounds which are presently used with many natural and synthetic rubbers.

Description : In vulcanization, natural rubber is heated with- (1) Carbon (2) Sulphur (3) Silicon (4) Phosphorus

Last Answer : (2) Sulphur Explanation: Vulcanization of rubber is a process of improvement of the rubber elasticity and strength by heating it in the presence of sulfur, which results in three-dimensional crosslinking of the chain rubber molecules (polyisoprene) bonded to each other by sulfur atoms.

Description : The element which is used for vulcanizing rubber – (1) Sulphur (2) Bromine (3) Silicon (4) Phosphorus

Last Answer : (1) Sulphur Explanation: Vulcanisation is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur or other equivalent "curatives" or "accelerators". By far the most common vulcanizing methods depend on sulfur.

Description : Which of the following substances would be the best choice to neutralize sulfuric acid? w) sodium hydroxide x) silicon dioxide y) copper metal z) phosphorus pentoxide

Last Answer : ANSWER: W -- SODIUM HYDROXIDE

Description : Which of the following substances would be the best choice to neutralize aqueous Sodium Hydroxide? w) sodium carbonate x) silicon dioxide y) aluminum oxide z) phosphorus pentoxide

Last Answer : ANSWER: Z -- PHOSPHORUS PENTOXIDE

Description : In commercial vulcanization, crosslinking is introduced by the addition of: w) sulfur x) toluene y) silicon z) phosphorus

Last Answer : ANSWER: W -- SULFUR

Description : The element which is used for vulcanizing rubber (1) Sulphur (2) Bromine (3) Silicon (4) Phosphorus

Last Answer : Sulphur

Description : Atomic number of which of the following elements is greater than that of Fluorine? (1) Sodium (2) Beryllium (3) Nitrogen (4) Boron

Last Answer : (1) Sodium Explanation: Sodium has higher atomic number (11) than Fluorine (9) The atomic number of Beryllium and Nitrogen are 4 and 7 respectively.

Description : (a) Define a balanced chemical equation. Why should an equation be balanced? (b) Write the balanced chemical equation for the following reaction: (i) Phosphorus burns in presence of chlorine to form phosphorus penta chloride. (ii) Burning of natural gas. (iii) The process of respiration. -Chemistry

Last Answer : Answer. (a) Balanced chemical equation has an equal number of atoms of different elements in the reactants and products. According to law of conservation of mass, matter can neither be created nor be destroyed in a chemical ... C6H12O6 (s) + 6O2 (g) + 6H2O ---> 6CO2 (aq) + 12H2O (l) + energy

Description : Which of the following is Colourless? (1) Chlorine (2) Oxygen (3) Phosphorus (4) Sulphur

Last Answer : (2) Oxygen

Description : Which of the following is colourless ? (1) Chlorine (2) Oxygen (3) Phosphorus (4) Sulphur

Last Answer : Oxygen

Description : Which of the following is an essential element used in the synthesis of proteins and other compounds? (1) Phosphorus (2) Iron (3) Magnesium (4) Nitrogen

Last Answer : (4) Nitrogen Explanation: Although all of the elements above are used by plants and taken up via the soil, nitrogen is especially essential and used specifically for the for the synthesis of proteins and other compounds.

Description : Which of the following is not a donor atom? (1) Phosphorus (2) Antimony (3) Arsenic (4) Aluminium

Last Answer : (4) Aluminium Explanation: Aluminium is an acceptor atom, an impurity atom in a semiconductor, which can accept or take up one or more electrons from the crystal and become negatively charged. In semiconductor physics. It is a dopant atom that when added to a semiconductor can form a ptype region.

Description : Which of the following is not a donor atom? (1) Phosphorus (2) Antimony (3) Arsenic (4) Aluminium

Last Answer : (4) Aluminium Explanation: Aluminium is an acceptor atom, an impurity atom in a semiconductor, which can accept or take up one or more electrons from the crystal and become negatively charged.

Description : Which of the following is not a donor atom? (1) Phosphorus (2) Antimony (3) Arsenic (4) Aluminium

Last Answer : Aluminium

Description : The element used for making solar cells is - (1) Magnesium (2) Sodium (3) Calcium (4) Silicon

Last Answer : (4) Silicon Explanation: Materials presently used for photovoltaic solar cells include mono-crystalline silicon, polycrystaijhne silicon, amorphous silicon, cadmium telluride, and copper indium selenideisulfide.

Description : What is the element that is in the highest percentage in the composition of the earth? (1) Silicon (2) Oxygen (3) Magnesium (4) Iron

Last Answer : (2) Oxygen Explanation: Earth, our home, is the third planet from the sun. It is the only planet known to have an atmosphere containing free oxygen, oceans of liquid water on its surface, and, of ... of it in the oceans. About a fifth of its atmosphere is made up of oxygen, produced by plants.

Description : The element used in the manufacture of safety matches is – (1) Phosphorous (2) Magnesium (3) Silicon (4) Sulphur

Last Answer : (1) Phosphorous Explanation: One end of a match is coated with a material that can be ignited by frictional heat generated by striking the match against a suitable surface. The coated end ... ," contains either phosphorus or phosphorus sesquisulfide as the active ingredient and gelatin as a binder.

Description : Mendeleev proposed the existence of an unknown element that he called eka-aluminum. The element is now called: w) magnesium x) silicon y) gallium z) germanium

Last Answer : ANSWER: C -- GALLIUM

Description : The element used for making solar cells is (1) Magnesium (2) Sodium (3) Calcium (4) Silicon

Last Answer : Silicon

Description : The element used in the manufacture of safety matches is (1) Phosphorous (2) Magnesium (3) Silicon (4) Sulphur

Last Answer : Phosphorous

Description : What is the element that is in the highest percentage in the composition of the earth ? (1) Silicon (2) Oxygen (3) Magnesium (4) Iron

Last Answer : Oxygen

Description : Non-metallic character increases from (1) Magnesium to Barium (2) Potassium to Cesium (3) Oxygen to Selenium (4) Sodium to Chlorine

Last Answer : (4) Sodium to Chlorine Explanation: The elements which lose electrons to form cations are known as metals. Metallic character decreases across a period as we move from left to right.

Description : Write balanced chemical equations for the following word equations: (a) Iron + Chlorine → Iron (III) chloride (b) Magnesium + dil sulphuric acid → Magnesium sulphate + water (c) Magnesium + oxygen → ... oxide (d) Calcium oxide + water → Calcium hydroxide (e) Sodium + chlorine → Sodium chloride

Last Answer : (a) Iron + Chlorine → Iron (III) chloride 4Fe + 3Cl2 → 2F2Cl3 (b) Magnesium + dil sulphuric acid → Magnesium sulphate + water 2Mg + 2H2SO4 → 2MgSO4 + 2H2 (c) Magnesium + oxygen → Magnesium oxide 2Mg ... hydroxide CaO + H2O → Ca(OH)2 (e) Sodium + chlorine → Sodium chloride 2Na + Cl2 → 2NaCl

Description : What is the atomic number of phosphorus ?

Last Answer : The atomic number of phosphorus is 15 .

Description : (3) preventing rapid setting of cement Explanation: Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, the remainder consisting of ... mixed with water by way of a complex series of chemical reactions still only partly understood.

Last Answer : Milk is a colloidal system in which: (1) Water is dispersed in fat (2) Fat is dispersed in water (3) Fat and water are dispersed in each other (4) Fat is dissolved

Description : Why are cimetidine or ranitidine better antacids than sodium bicarbonate or magnesium or aluminium hydroxide ? 

Last Answer : Ans. If excess of NaHCO3 or Mg (OH)2 or Al (OH)3 is used, it makes the stomach alkaline and thus triggers the release of even more HCl. In contrast, cimetidine or ranitidine prevent the interaction of histamine with the receptor cells in the stomach wall and thus release lesser amount of HCl. 

Description : Hydrofluoric acid is not kept in glass bottles because it reacts with - (1) visible light (2) silicon dioxide of glass (3) aluminium oxide of glass (4) sodium oxide of glass

Last Answer : (2) silicon dioxide of glass

Description : The element present in the largest amount in rocks and minerals is - (1) carbon (2) silicon (3) hydrogen (4) aluminium

Last Answer : (2) silicon Explanation: Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure free element in nature. It is most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates.

Description : Major portion of the earth's crust is mainly constituted by – (1) Oxygen and Iron (2) Oxygen and Silicon (3) Silicon and Iron (4) Silicon and Aluminium

Last Answer : (2) Oxygen and Silicon Explanation: Oxygen is the most abundant element in the earth's crust, comprising 46.6% or the crust by weight. Silicon 28%, aluminum 8.2%, iron 5.6%, calcium 4.2% ... Given the abundance of oxygen and silicon, the silicates are the most abundant minerals in the earth's crust.

Description : Major portion of the earth’s crust is mainly constituted by (1) Oxygen and Iron (2) Oxygen and Silicon (3) Silicon and Iron (4) Silicon and Aluminium

Last Answer : Oxygen and Silicon

Description : Antacid tablets consist of – (1) Hydroxides of sodium, magnesium and aluminium (2) Hydroxides of magnesium and aluminium (3) Hydroxides of sodium and aluminium (4) Hydroxides of magnesium and sodium

Last Answer : (2) Hydroxides of magnesium and aluminium Explanation: An antacid is a base which neutralizes stomach acidity. The most common of these bases are hydroxides, carbonates, or bicarbonates such as Aluminum hydroxide, Calcium. carbonate, Magnesium carbonate, Magnesium hydroxide, and Sodium bicarbonate.

Description : Philosopher’s wool is chemically - (1) Aluminium oxide (2) Magnesium oxide (3) Zinc oxide (4) Calcium oxide

Last Answer : (3) Zinc oxide Explanation: Philosopher's Wool is chemically zinc oxide.

Description : Which of the following is the most abundant metal on Earth's crust? (1) Magnesium (2) Iron (3) Copper (4) Aluminium

Last Answer : (4) Aluminium Explanation: Aluminum is the most abundant metal in the Earth's crust, and the third most abundant element therein, after oxygen and silicon. It makes up about 8% by weight of the Earth's solid ... of Earth's volume Oxygen is 46.6%, Silicon 27.77%, Aluminum is 8.09% and iron is 5%.

Description : Although thermodynamically feasible, in practice, Magnesium metal is not used for the reduction of Alumina in the metallurgy of aluminium.Why?

Last Answer : Ans. : Below the temperature(1623 K) correspoinding to the point of intersection of Al 2O3 and MgO curves in Ellingham diagram, Magnesium can reduce Alumina because the ΔfG o value of Al2O3 at ... to Al. But Magnesium is much costier metal than Aluminium and hence the process will be uneconomical.