If all the ions from (i) one of the rectangular planes passing through opposite face centres as well as (ii) one of triad axis of symmetry are removed then which one of the following statements is incorrect? (Ignore charge balance)
(A) Formula of NaCl become `Na_(8)Cl_(7)`
(B) Formula of `Na_(2)O` became `Na_(24)O_(7)`
(C) Formula of ZnS become `Zn_(3)S_(7)`
(D) Formula of `CaF_(2)` become `Ca_(7)F_(24)`

A : If a tetrad axis is passed through the unit cell of NaCl and all ions removed which are touching to tetrad axis then the formula of NaCl becomes Na_(3)Cl_(4) . R : Only one Na^(+) is removed not the Cl^(-) .

A compound formed by elements X and Y has a cubic structure in which X atoms are at the corner of the cube and also at the face centers. Y atoms are present at the body centre and at the edge centre of the cube. a. Celculate (i) Z_(eff') (ii) total number of atoms in the cube, and (iii) formula of the compound. b. If all the atoms are removed from one of the body diagonals of the cube, calculate (i) Z_(eff') (ii) total number of atoms in the cube, and (iii) formula of the compound. c. If all the atoms from the diagonals of the one of the face of the cube are removed, calculate (i) Z_(eff') (ii) total number of atoms in the cube, and (iii) formula of the compound. d. If all the atoms are removed from one of the plane passing through the middle of t he cube, calculate (i) Z_(eff') (ii) total number of atoms in the cube, and (iii) formula of the compound. e. If all the atoms are removed from one of the axes passing through one of the face centres of the cube, calculate (i) Z_(eff') (ii) total number of atoms in the cube, and (iii) formula of the compound.

If a solid A^(o+)B^(ɵ) having ZnS Structure is heated so that the ions along two of the axis passing throgh the face centre particles are lost and bivalent ion (Z) enters herre to maintain the electrical neutrality, so that the new formula unit becomes A_(x)B_(y)Z_(c) , report the value of x + y + c .

Which one of the following will have the largest number of atoms? a)1g Fe(at. mass -56) b)1g Na (at. mass-23) c)1g Li (at. mass-7) d)1g F2 (at. mass-19)

Let T be the line passing through the points P(-2,\ 7) and Q(2,\ -5) . Let F_1 be the set of all pairs of circles (S_1,\ S_2) such that T is tangent to S_1 at P and tangent to S_2 at Q , and also such that S_1 and S_2 touch each other at a point, say, M . Let E_1 be the set representing the locus of M as the pair (S_1,\ S_2) varies in F_1 . Let the set of all straight lines segments joining a pair of distinct points of E_1 and passing through the point R(1,\ 1) be F_2 . Let E_2 be the set of the mid-points of the line segments in the set F_2 . Then, which of the following statement(s) is (are) TRUE? The point (-2,\ 7) lies in E_1 (b) The point (4/5,7/5) does NOT lie in E_2 (c) The point (1/2,\ 1) lies in E_2 (d) The point (0,3/2) does NOT lie in E_1

Consider the following equation H_(4)P_(2)O_(7) + 2NaOH to Na_(2)H_(2)P_(2)O_(7) + 2H_(2)O If 534 gm of H_(4)P_(2)O_(7) is reacted with 3.0 xx 10^(24) formula units of NaOH ,then total number of moles of H_(2)O is produced is ( N_(A) = 6 xx 10^(23) )

Three atoms A, B and C crystallize in a cubic solid lattice where A atoms are present at the body centre, B atoms are present at the edge centre as well as at the corners of the cube and C atoms are present at the face centres of the cube. Now if all the atoms are removed from the two 4-fold axis and the one 2-fold axis passing through the cube, then the formula of the compound is

Same quantity of current is passed through molten NaCl and molten cryolite containing Al_(2)O_(3) . If 4.6g of Na was liberated in one cell, the mass of Al liberated in the other cell is 1) 0.9g 2) 1.8g 3) 2.7g 4) 3.6g

If all the atoms touching one face plane are removed in solid A^(o+)B^(Θ) having rock salt type structure, then the formula of the compound left and the defect brought by this removal, respectively, is a. AB , Frenkel defect b. A_(2)B , Frenkel defect c. AB , Schottky defect d. A_(2)B , Schottky defect

Among the following ,what is the total number of speices which are very good oxidising agents/reducing agents/neither oxidising nor reducing ones ? a. F_(2) b. F^(ө) c. Na d. Na^(o+) e. MnO_(4)^(ө) f. I^(ө) Cl^(ө) h. Ce^(4+) i. Cr_(2)O_(7)^(2-) j. CrO_(4)^(2-) k. HNO_(3) l. Fe^(2+)