Discuss briefly de-mineralisation
Question: Discuss briefly de-mineralisation of water by ion exchange resin. Solution: Demineralised water is obtained by ion exchange resin by passing it through an anion exchange and cation exchange resin. Those resins have large SO3H and COOH groups. The water is passed through cation exchanger which removes cations like Na+ and Mg+ Now, this water coming out from cation exchanger is acidic, therefore it is passed through the anionic exchanger which removes anions like OH-, NO3-, etc. by excha...
Read More →What do you understand by
Question: What do you understand by the term auto protolysis of water? What is its significance? Solution: Auto protolysis of water is self ionisation of water. It is one of the chemical properties of water. Here, two same molecules react to give ions involving proton transfer....
Read More →Give reasons:
Question: Give reasons: (i) Lakes freeze from top towards bottom. (ii) Ice floats on water. Solution: (i) The density of ice is less than water. Coldwater starts expanding and becomes less dense than what it should be when the temperature drops to 4C. As a result, cold water being less dense floats on to the surface and when it comes to the chilly freezing weather conditions outside, it gets frozen. (ii) the density of ice is lower than water and hence ice floats on water....
Read More →Complete the following equations:
Question: Complete the following equations: (i) PbS (s) + H2O2 (aq) (ii) CO (g) + 2H2 (g) Solution: (i) PbS (s) + H2O2 (aq) PbSO4 + 4H2O (ii) CO (g) + 2H2 (g) CH3OH...
Read More →If the same mass of liquid water and
Question: If the same mass of liquid water and a piece of ice is taken, then why is the density of ice less than that of liquid water? Solution: On freezing water expands and the volume of ice for the same mass of water will be more than that of the water. We can say that the density of ice is lower than water and hence floats on water....
Read More →Name the classes of hydrides to which H2O,
Question: Name the classes of hydrides to which H2O, B2 H6 and NaH belong. Solution: H2O Electron rich hydride B2H6 Electron deficient hydride. NaH Ionic hydride....
Read More →What are metallic/interstitial hydrides?
Question: What are metallic/interstitial hydrides? How do they differ from molecular hydrides? Solution: Metallic hydrides are those compounds which are formed when the transition element reacts with hydrogen. Eg. CaH₂, LiBH₄ Molecular hydrides are formed by the combination of an element which is having comparable higher electronegativity with hydrogen. Eg. H₂O, B₂H₆...
Read More →How can production of hydrogen from water
Question: How can production of hydrogen from water gas be increased by using water gas shift reaction? Solution: The water shift gas reaction is used in the formation of synthesis gas hydrogen and carbon monoxide or carbon dioxide mixture. Here CO is converted to CO2 and H2 is also obtained from water....
Read More →Which of the following statements is correct?
Question: Which of the following statements is correct? (i) Metallic hydrides are deficient of hydrogen. (ii) Metallic hydrides conduct heat and electricity. (iii) Ionic hydrides do not conduct electricity in solid-state. (iv) Ionic hydrides are very good conductors of electricity in solid-state. Solution: Option (i)Metallic hydrides are deficient of hydrogen , (ii)Metallic hydrides conduct heat and electricityand (iii)Ionic hydrides do not conduct electricity in solid-state are the answers....
Read More →Which of the following statements is correct?
Question: Which of the following statements is correct? (i) Hydrides of group 13 act as Lewis acids. (ii) Hydrides of group 14 are electron deficient hydrides. (iii) Hydrides of group 14 act as Lewis acids. (iv) Hydrides of group 15 act as Lewis bases. Solution: Option (i) and (iv) are the answers....
Read More →Which of the following statements is correct?
Question: Which of the following statements is correct? (i) Elements of group 15 form electron deficient hydrides. (ii) All elements of group 14 form electron precise hydrides. (iii) Electron precise hydrides have tetrahedral geometries. (iv) Electron rich hydrides can act as Lewis acids. Solution: Option (ii) and (iii) are the answers....
Read More →The hardness of water may be temporary
Question: The hardness of water may be temporary or permanent. Permanent hardness is due to the presence of (i) Chlorides of Ca and Mg in water (ii) Sulphates of Ca and Mg in water (iii) Hydrogen carbonates of Ca and Mg in water (iv) Carbonates of alkali metals in water Solution: Option (i) and (ii) are the answers....
Read More →Some of the properties of water are described below.
Question: Some of the properties of water are described below. Which of them is/are not correct? (i) Water is known to be a universal solvent. (ii) Hydrogen bonding is present to a large extent in liquid water. (iii) There is no hydrogen bonding in the frozen state of water. (iv) Frozen water is heavier than liquid water. Solution: Option (iii) and (iv) are the answers....
Read More →Which of the following statements about hydrogen
Question: Which of the following statements about hydrogen are correct? (i) Hydrogen has three isotopes of which protium is the most common. (ii) Hydrogen never acts as a cation in ionic salts. (iii) The hydrogen ion, H+, exists freely in solution. (iv) Dihydrogen does not act as a reducing agent. Solution: Option (i) and (ii) are the answers....
Read More →Which of the following statement(s)
Question: Which of the following statement(s) is/are correct in the case of heavy water? (i) Heavy water is used as a moderator in a nuclear reactor. (ii) Heavy water is more effective as a solvent than ordinary water. (iii) Heavy water is more associated than ordinary water. (iv) Heavy water has a lower boiling point than ordinary water. Solution: Option (i)Heavy water is used as a moderator in a nuclear reactor and (iii)Heavy water is more effective as a solvent than ordinary water are the ans...
Read More →Dihydrogen can be prepared on a commercial
Question: Dihydrogen can be prepared on a commercial scale by different methods. In its preparation by the action of steam on hydrocarbons, a mixture of CO and H2 gas is formed. It is known as ____________. (i) Water-gas (ii) Syngas (iii) Producer gas (d) Industrial gas Solution: Option (i)Water-gas and (ii) Syngas are the answers....
Read More →Which of the following statements
Question: Which of the following statements are not true for hydrogen? (i) It exists as a diatomic molecule. (ii) It has one electron in the outermost shell. (iii) It can lose an electron to form a cation which can freely exist (iv) It forms a large number of ionic compounds by losing an electron Solution: Option (iii) and (iv) are the answers....
Read More →Only one element of ________ forms hydride.
Question: Only one element of ________ forms hydride. (i) group 6 (ii) group 7 (iii) group 8 (iv) group 9 Solution: Option (i)group 6 is the answer....
Read More →Elements of which of the following group(s)
Question: Elements of which of the following group(s) of periodic table do not form hydrides. (i) Groups 7, 8, 9 (ii) Group 13 (iii) Groups 15, 16, 17 (iv) Group 14 Solution: Option (i)Groups 7, 8, 9 is the answer....
Read More →Which of the following compounds
Question: Which of the following compounds is used for water softening? (i) Ca3 (PO4) (ii) Na3PO4 (iii) Na6P6O18 (iv) Na2HPO4 Solution: Option (iii)Na6P6O18 is the answer....
Read More →Which of the following ions will cause
Question: Which of the following ions will cause hardness in the water sample? (i) Ca2+ (ii) Na+ (iii) Cl (iv) K+ Solution: Option (i)Ca2+ is the answer....
Read More →Which of the following reactions is an example
Question: Which of the following reactions is an example of use of water gas in the synthesis of other compounds? (i) CH4 (g) + H2O (g) (1270KNi) CO (g) + H2 (g) (ii) CO (g) + H2O (g) (Catalyst673K) CO2 (g) + H2 (g) (iii) CnH2n+2 + nH2O (g) (1270KNi) nCO + (2n+1) H2 (iv) CO (g) + 2H2 (g) Cobalt (Catalyst) CH3OH (l) Solution: Option (iv) CO (g) + 2H2 (g) Cobalt (Catalyst) CH3OH (l)is the answer....
Read More →Hydrogen peroxide is obtained by
Question: Hydrogen peroxide is obtained by the electrolysis of ______. (i) water (ii)sulphuric acid (iii) hydrochloric acid (iv) fused sodium peroxide Solution: Option (ii) sulphuric acidis the answer....
Read More →When sodium peroxide is treated with
Question: When sodium peroxide is treated with dilute sulphuric acid, we get ______. (i) sodium sulphate and water (ii) sodium sulphate and oxygen (iii) sodium sulphate, hydrogen and oxygen (iv) sodium sulphate and hydrogen peroxide Solution: Option (iv) sodium sulphate and hydrogen peroxide is the answer....
Read More →The angle of intersection of the parabolas
Question: The angle of intersection of the parabolas $y^{2}=4$ ax and $x^{2}=4$ ay at the origin is A. $\frac{\pi}{6}$ B. $\frac{\pi}{3}$ C. $\frac{\pi}{2}$ D. $\frac{\pi}{4}$ Solution: Given that the the parabolas $y^{2}=4 a x$ and $x^{2}=4 a y$ Differentiating both w.r.t. $\mathrm{x}$, $2 y \frac{d y}{d x}=4 a$ and $2 x=4 a \frac{d y}{d x}$ $\frac{d y}{d x}=\frac{2 a}{y}=m_{1}$ and $\frac{d y}{d x}=\frac{x}{2 a}=m_{2}$ At origin, $m_{1}=$ infinity and $m_{2}=0$ $\tan \theta=\left|\frac{\mathrm...
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