Explain why bond angle of h2o is greater than of2

It's only a small difference (103 degrees versus 104 degrees in water), and I believe the usual rationalization is that since F is more electronegative than H, the electrons in the O-F bond spend more time away from the O (and close to the F) than the electrons in the O-H bond. That shifts the effective center of the repulsive force between the bonding pairs away from the O, and hence away from each other. So the repulsion between the bonding pairs is slightly less, while the repulsion between the lone pairs on the O is the same -- the result is the angle between the bonds is a little less.

Hope this helps!

Hi + naoh -> h2o + nal

  balanced chemical equations follow the law of conservation of mass and charges. the masses and charges on either sides of the equation should be balanced.in conservation of mass, the number of atoms of each element on left side should be equal to the number of atoms of each element on the right side of the equation.1)k₂so₄ + 2ca(no₃)₂ --> 2kno₃ + 2caso₄number of ions        left side             right side  k⁺         2                         2so₄²⁻   1                         2ca²⁺     2                         2no₃⁻     4                         2in this equation the masses of so₄²⁻ and no₃ are not balanced. therefore this equation violates the law of conservation of mass2)ti + 2 cl₂ > ticl₄        left side       right side  ti           1               1cl           4               4this equation follows the law of conservation of mass3)2c₂h₂ + 5o₂ > 4co₂   + 2h₂o              left side     right side  c               4               4h               4               4o             10             10this equation follows the law of conservation of mass4)baso₄ + 2naoh --> ba(oh)₂   + na₂so₄          left side       right side  ba       1                   1so₄²⁻     1                   1na         2                   2  oh⁻       2                   2this equation follows the law of conservation of massanswer is 1st equation