Description : (3) reflection of light due to the presence of free electrons Explanation: Lustre (or luster) is the way light interacts with the surface of a crystal, rock, or mineral. The word ... conductivity, and high density. Typically they are malleable and ductile, deforming -under stress without cleaving.
Last Answer : Cloud is a colloidal dispersion of – (1) Air in a dispersion medium of water (2) Fog in a dispersion medium of water (3) Mist in a dispersion medium of air (4) Water drops in a dispersion medium of air
Description : Assertion : - Cockorach undergoes many moulting in their development stage. Reason : - Cockroach exhibits gradual metamorphosis.
Last Answer : Assertion : - Cockorach undergoes many moulting in their development stage. Reason : - Cockroach exhibits gradual metamorphosis. A. A B. B C. C D. D
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 : (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 : From the elements: Cl, Br, F, O, Al, C, Li, Cs and Xe; choose the following: (a) The element with highest negative electron gain enthalpy. (b) The element with lowest ionization enthalpy. ( ... . (f)The element which belongs to zero group. (g) The elements which forms largest number of compounds.
Last Answer : Ans. (a). The element chlorine (Cl) has the highest negative electron gain enthalpy. (b). The element cesium (Cs) has lowest ionization enthalpy. (c). The element fluorine F has lowest atomic radius. (d ... zero group (or group 18). (g). The element carbon (C) forms the largest number of compounds.
Description : Which one of the following statements concerning elements in the Periodic Table is correct? A Elements of the same group all have the same number of electrons in the outermost occupied electron shell. B ... (Group 17) are all gases at room temperature. E The Group 13 elements are all metals.
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 : Give reason for the following: (a) Aluminium oxide is considered as an amphoteric oxide. (b) Ionic compounds conduct electricity in molten state. -Chemistry
Last Answer : a) Aluminium oxide reacts with both acids as well as bases.b) Ionic compounds in molten state conduct electricity. Explanation: a) An amphoteric oxide as one that shows chemical reactivity with ... ions are present in the liquid state. These free ions enable the solution to conduct electricity.
Description : Assertion (A): Micelles are formed by surfactant molecules above the critical micellization concentration `(CMC)` . Reason(R): The conductivity of a s
Last Answer : Assertion (A): Micelles are formed by surfactant molecules above the critical micellization concentration ` ... If both Assertion & Reason are False.
Description : A single covalent bond (a) Is formed by the transfer of two electrons (b) Exists between hydrogen and chlorine in an aqueous solution, of hydrochloric acid (c) Is longer than a double bond (d) Does not require energy to disrupt it unlike an ionic bond
Last Answer : Ans:(c)
Description : Give reason .the compounds of alkaline earth metals are less ionic than alkali metals
Last Answer : Ans This is due to increased nuclear charge and smaller size.
Last Answer : This is due to increased nuclear charge and smaller size.
Description : Which is an element which never exhibits positive oxidation state in any of its compounds? -Do You Know?
Last Answer : answer:
Description : In which of the following compounds, nitrogen exhibits highest oxidation state ?
Last Answer : In which of the following compounds, nitrogen exhibits highest oxidation state ? A. `N_(3)H` B. `NH_(2)OH` C. `N_(2)H_(4)` D. `NH_(3)`
Description : In which of the following compounds oxygen exhibits an Oxidation state of `+2`
Last Answer : In which of the following compounds oxygen exhibits an Oxidation state of `+2` A. `H_(2)O` B. `H_(2)O_(2)` C. `OF_(2)` D. `H_(2)SO_(4)`
Description : Which is an element which never exhibits positive oxidation state in any of its compounds?
Last Answer : Fluorine
Description : In which of the following compounds, nitrogen exhibits highest oxidation state? (1) NH2OH (2) N2H4 (3) NH3 (4) N3H
Last Answer : N3H
Description : Sodium dissolves in liquid ammonia to form a solution which shows electrical conductivity.
Last Answer : Explain : Sodium dissolves in liquid ammonia to form a solution which shows electrical conductivity.
Description : Assertion :- Oxidation number of `S` in `HSO_(3)^(-)` is `+4`. Reason :- Sulphur is in different oxidation state in different compounds.
Last Answer : Assertion :- Oxidation number of `S` in `HSO_(3)^(-)` is `+4`. Reason :- Sulphur is in ... Reason is False. D. If both Assertion & Reason are False.
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 : Which one of the following elements exhibits the greatest tendency to lose electrons? (1) Fluorine (2) Lithium (3) Oxygen (4) Zine
Last Answer : (2) Lithium Explanation: Alkali metals such as Lithium are the most electropositive elements in the periodic table. As alkali metals have low ionization energies, they have a great tendency to lose electrons forming unipositive ions.
Description : Which one of the following elements exhibits the greatest tendency to lose electrons ? (1) Fluorine (2) Lithium (3) Oxygen (4) Zinc
Last Answer : Lithium
Description : Which of the following will exhibit maximum ionic conductivity ?
Last Answer : Which of the following will exhibit maximum ionic conductivity ? A. `K_(4)[Fe(CN_(6))]` B. `[Co(NH_(3))_(6]Cl_(3 ... 3))_(4)]Cl_(2)` D. `[Ni(CO)_(4)]`
Description : Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: During biodegradation of organic compounds. Oxy
Last Answer : Assertion: Amount of biodegradable organic matter present in water is measured by BOD of water Reason: ... but reason is wrong D. both are wrong
Description : Assertion : Organichlorine presticides are organic compounds that have been chlorinated. Reason:Fenitrothion is one of the organochlorine pesticides.
Last Answer : Assertion : Organichlorine presticides are organic compounds that have been chlorinated. Reason:Fenitrothion is ... reason is wrong D. Both are wrong
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 : Assertion: Light-harvesting complexes (LHC) on thylkoid membrane broaden the range of light absorption: Reason: They transfer electrons to reaction ce
Last Answer : Assertion: Light-harvesting complexes (LHC) on thylkoid membrane broaden the range of light absorption: ... . If both Assertion and Reason are false.
Description : Assertion:- `N_(2)^(+)` is more stable than `N_(2)^(-)` Reason:- `N_(2)^(+)` has less electrons in antibonding orbital .
Last Answer : Assertion:- `N_(2)^(+)` is more stable than `N_(2)^(-)` Reason:- `N_(2)^(+)` has ... the Reason is False. D. If both Assertion & Reason are false
Description : Assertion:- In MgO electrovalency of Mg is 2. Reason :- Mg shares two electrons with oxygen.
Last Answer : Assertion:- In MgO electrovalency of Mg is 2. Reason :- Mg shares two electrons with oxygen. A. If ... False. D. If both Assertion & Reason are false
Description : Assertion :- First electrons affinity fo all element is positive. Reason :- Successive electron affinity of all elements is negative
Last Answer : Assertion :- First electrons affinity fo all element is positive. Reason :- Successive electron affinity ... D. If both Assertion & Reason are false
Description : Assertion : In a radioactive disintegration, an electron is emitted by the nucleus. Reason : Electrons are always present inside the nucleus.
Last Answer : Assertion : In a radioactive disintegration, an electron is emitted by the nucleus. Reason : Electrons are ... both (A) and (R ) are incorrect.
Description : Assertion : Inside a conductor, electrons have no motion in the absence of some potential difference across it. Reason : In the absence of potential d
Last Answer : Assertion : Inside a conductor, electrons have no motion in the absence of some potential difference ... D. If both Assertion and Reason are false.
Description : Assertion : Current between two points in an electrical always flows from higher potential to lower potential. Reason : During charging of a battery c
Last Answer : Assertion : Current between two points in an electrical always flows from higher potential to lower ... . If both Assertion and Reason are false.
Description : What is modern theory about the existence of the ionic compounds in solid state?
Last Answer : Ans: According to modern theory these exist in form of ions even in solid state for example, sodium chloride exist as Na+ Cl- . Whereas according to the ionic theory it exists as NaCl.
Description : Why ionic compounds are non conductor in solid state and conductor in molten or fused state?
Last Answer : Ans: This is because in solid state there are no free ions and their free movement isn’t possible but in molten or fused state the free movement of ions is possible, so these can conduct electric current.
Description : Arrange the following compounds in order of increasing molar conductivity . `(i) K[Co(NH_(3))_(2)(NO_(2))_(4)]" " (ii) [Cr(NH_(3))_(3)(NO_(2))_(3)]` `
Last Answer : Arrange the following compounds in order of increasing molar conductivity . `(i) K[Co(NH_(3))_(2)(NO_(2))_(4)]" ... )" " (iv) [Cr(NH_(3))_(6)]Cl_(3)`
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 : Pick out the wrong statement. (A) Copper is the metal having the highest electronic conductivity (B) Hardenability & Weldability of metals are inversely related (C) Covalent bonding formed by ... all semiconductor materials (D) Glass transition temperature applies to 'polymers' but not to 'glasses'
Last Answer : Option A
Description : Assertion :- A gas mixed with another gas forms a colloidal solution. Reason :- Mixture of gases is homogenous system.
Last Answer : Assertion :- A gas mixed with another gas forms a colloidal solution. Reason :- Mixture of gases is ... . D. If both Assertion & Reason are False.
Description : Assertion: `Ag` and `Au` are extracted by leaching the ores with a dilute solution of `NaCN`. Reason: Impurities associated with these ores dissolve i
Last Answer : Assertion: `Ag` and `Au` are extracted by leaching the ores with a dilute solution of `NaCN`. ... . Statement-1 is false but Statement -2 is true
Description : Assertion : A white turbidity is obtained by passing `H_(2)S` through aq solution of `SO_(2)` Reason: Aq solution of `SO_(2)` and `H_(2)S` undergoes r
Last Answer : Assertion : A white turbidity is obtained by passing `H_(2)S` through aq solution of `SO_(2 ... Statement-I is not correct and Statement-II is correct
Description : Assertion (A):A pair of linear equations has no solution (s) if it represented by intersecting lines graphically. Reason (R) : If the pair of lines are intersecting, then the pair has unique solution and is called ... of A. (c) A is correct; R is incorrect. (d) R is correct; A is incorrect.
Last Answer : (d) R is correct; A is incorrect.
Description : Assertion (A) : The value of k for which the system of linear equations kx+2y+1=0 and 6x+4y-5=0 has a unique solution is 3. Reason (R):The system of linear equations a1x + b1y + c1= 0 and a2x + ... not the correct explanation of A. (c) A is correct; R is incorrect. (d) R is correct; A is incorrect.
Description : Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]. Assertion: Fast decoupled load flow method gives approximate load flow solution because it uses several assumptions. Reason: Accuracy ... the correct reason for [a]. c) [a] is false and [r] is true.
Last Answer : c) [a] is false and [r] is true
Description : Why do metals conduct electricity but crystals of ionic compounds do not conduct electricity ?
Last Answer : Metals have free electrons. These electrons, created to gain the electromagnetic positivity and octal structure of the metal, flow from the negative side of the electric source to the positive edge ... electrons does not occur in it. Therefore crystals of ionic compounds do not conduct electricity.
Description : What are the common denominators of ionic compounds ?
Last Answer : Ionic compounds have some common properties. These are: 1. All ionic compounds are in the form of crystals or crystals in solid state. 2. When the electronic structure of different ... ionic compounds is extremely fast. . In chemical reactions ions of ionic compounds retain their individuality.
Description : Which of the following compounds has ionic bond. `pi-`bond, co-ordinate bond and covalent bond:-
Last Answer : Which of the following compounds has ionic bond. `pi-`bond, co-ordinate bond and covalent bond:- A. `HNO_(2)` B. `NaNO_(3)` C. `KNO_(2)` D. `MgCl_(2)`
Description : Oxygen differs from the other elements of the group. Compounds of oxygen with metals are more ionic in nature and hydrogen bonding is more important f
Last Answer : Oxygen differs from the other elements of the group. Compounds of oxygen with metals are more ionic in nature ... H_(2)O lt H_(2)Te -` boiling point
Last Answer : Oxygen differs from the other elements of the group. Compounds of oxygen with metals are more ... oxides are usually covalent and acidic in nature