Mehapatel

∵   297 = 300 - 3 and 303 = 300 + 3
∴   297 x 303 = (300 - 3) (300 + 3)               = (300)2 - (3)2                            [Using (a + b)(a - b) = a2 -b2]              = 90000 - 9              = 89991

Solution:Mass of acetic acid  W1= 75g Molar mass of C6H8O6                = 6×12+8×1+6×16= 72+8+96 = 176 g mol-1lowering of melting point , ∆Tf = 1.5 kWe know that:∆Tf  =Kf×w2×1000M2×w1  =  w2 = ∆Tf×M2×w1Kf×1000         =1.5×176×753.9×1000  = 5.08g approx.  
 
Hence, 5.08 g of ascorbic acid is needed to be dissolved. 

So,    BP = BQ(Tangents from external point B)But    BP = 27 cm⇒    BQ = 27 cmIt is given that BC = 38 cm⇒    BQ + CQ = 38⇒    27 + CQ = 38⇒    CQ = 11 cm⇒ CQ = CR (Tagents from an external point C)But    CQ = 11 cm⇒    CR = 11 cm
It is given that : CD = 25 cm⇒    CR + DR = 25⇒    11 + DR = 25⇒    DR = 14 cmSince, tangent to a circle is perpendicular to the radius through the point of contact.∴ ∠ORD = ∠OSD = 90°It is given that∠D = 90°Now, in quadrilateral ORDS,∠ORD = ∠OSD = ∠RDS = ∠ROS = 90°and    OR = OS [radii of circle]Therefore, ORDS is a squareSo,    OR = DR = 14 cmHence    r = 14 cm.

(i) All Bronsted bases are also Lewis bases: According to Bronsted concept, the base is a substance which accepts a proton. According to Lewis concept, a base is a substance which can donate a pair of electron. Any substance which can donate a pair of an electron can easily accept a proton.Thus all Bronsted bases are all Lewis bases.(ii) All Bronsted acids are not Lewis acids: According to Bronsted concept, an acid is a substance that can donate a proton (H+). According to Lewis concept, an acid is any substance (molecule or ion) which can accept a pair of electrons from another substance to

Phenol is converted to benzene on heating with zinc dust. Further reaction with chlorine followed by FeCl3 gives chlorobenzene.

Mrs Pearson and Mrs Fitzgerald are two contrasting characters. Actually, they are foil to each other. Mrs Pearson is a pleasant looking woman in her forties. She appears to be confused and worried. Mrs Fitzgerald is older. She is heavier and has a ‘strong and sinister personality’. Mrs Pearson is timid and gentle. Mrs Fitzgerald is liberated and bold. She smokes and plays with cards. The two ladies have sharply contrasting voices. Mrs Pearson speaks in a ‘light, flurried sort of tone’. She has ‘a touch of suburban Cockney’. Mrs Fitzgerald has a deep voice. Her accent is Irish.
Mrs Pearson ha

Electronegativity, as well as ionisation energy both, usually decrease on moving downward a group with an increase in atomic number. The hydroxides and sulphates of alkaline earth metals are ionic solids and the solubility of ionic solids is governed by two factors viz, lattice energy and hydration energy. For solubility hydration, energy > lattice energy.Hydration energy varies inversely with size, ie, decreases with increase in size. However, lattice energy in case of sulphates, remains almost same with an increase in the atomic number of alkaline earth metals, due to the large size of sulp

Pandita Ramabai

Area of the square lawn PQRS = 42 m x 42 mLet OP = OS = xmSo, x2 + x2  = (42)2⇒ 2x2 = 42 x 42⇒ x2 = 21 x 42Now, area of sector POS= 

Crystal Field Splitting Energy: Crystal field theory was given to explain the structure and stability of the coordination complexes. This theory has some assumption like the metal ion is considered to be a point positive charge and the ligands are negative charge. The complexes are formed mainly by the d- block elements due to their variable oxidation states and variable coordination number. The d- subshell has 5 degenerate orbitals. when the ligand approach to the metal ion, the energy of the degenerate orbitals is increased and further splitting of degenerate orbital takes place into t2g an

The net force acting on the losing team is the resultant of the forces applied by the two teams. So, it undergoes displacement. Positive work is done by the winning team on the losing team. The force applied by the losing team is zero. This is because the winning team does not move. The losing team does not displace from its position and hence work done by the losing team is zero. 

(i)The poverty ratio is the highest in states like Orissa, Bihar and Madhya Pradesh.(ii)The poverty ratio is the lowest in the states like Jammu & Kashmir, Punjab and Himachal Pradesh.

(iii) In Na2O, ions present are Na+ and O–2.(iv) In MgO, ions present are Mg+2 and O–2.

Perpendicular bisector of A (1, 3) andB(- 3, 5) is,2x(x1 - x2) + 2y(y1 - y2) = x12 + y12 - x22 + y22⇒ 2x1 + 3 + 2y(3 - 5) = (1 + 9) - (9 + 25)⇒                        8x - 4y = 10 - 34⇒                   2x - y + 6 = 0            ...(i)Similarly, perpendicular bisector of A (1, 3) and C (5, - 1) is2x(1 - 5) + 2y(3 + 1) = (1 + 9) - (25 + 1)⇒              - 8x + 8y = 10 - 26⇒                  - x + y = - 2⇒               x - y - 2 = 0              ...(ii)Point of intersection of Eqs. (i) and (ii), is P = (- 8, - 10).Then, the distance between P and A is,      PA = 1 + 82 + 3 + 102     = 81 + 16

a) When an object is placed in front of the lens between its optical centre and principal focus, the image is formed beyond 2F1 (on the same side of the object), and the ray diagram is obtained is as follows:b) The object distance (u) and the image distance (v) are as shown below. Since both the image and the object lie in a direction opposite to the direction of incoming rays, the magnitude will be negative for both.

 
The relation between u, v and f is given by the lens formula,  c) Given, u = -20 cm m = -1 Since magnification  is given as, Focal length (f) can be calculated as: Thus, t

Solved Questions Answers and Assignments for STD 8 - Find GSEB Textbook solution for STD 8 Online ધોરણ 8 હિન્દી ગુજરાતી વિજ્ઞાન સંસ્કૃત સમાજશાસ્ત્ર

O2+ (15 e-) = K : K+ (σ2s)2 (σ*2s)2 (σ2px)2 (π2py)2 (π2pz)2 (π*2py)1 (π*2pz)0Hence , bond order = 12 (10 - 5) = 2.5N2+ (13e-) = KK* (σ2s)2 (σ*2s)2 (σ2px)2 (π2py)2 (π2pz)1Hence , bond order = 12 (9 - 4) = 2.5

Phosphorus is a component of DNA and RNA but not proteins.

जब अम्ल किसी क्षार से क्रिया करता है तब लवण और जल बनता हैl इसे उदासीनीकरण अभिक्रिया कहते हैंlक्षार + अम्ल → लवण + जलउदाहरण:NaOH + HCl → NaCl + H2O(क्षार)    (अम्ल)   (लवण)   (जल)KOH + HNO3 → KNO3 + H2O(क्षार)    (अम्ल)     (लवण)   (जल)

जलाशय - सर, सरोवर, तालाबसिंधु - सागर, समुंदर, रत्नाकरपंकज - नीरज, जलज, कमलपृथ्वी - धरा, भूमि, धरतीआकाश - अम्बर, नभ, व्योम