Complete and balance the following chemical reactions.
(i)`Cu(BO_(2))_(2) + C overset("fused") to` , (ii)`AgBr+"concentrated" NH_(3) to`
(iii)`Cr(OH)_(3) + Na_(2)CO_(3) + KNO_(3) overset ("fused")` , (iv)`Cu(NO_(3))_(2) overset(Delta) to`

Answer

(i)`2Cu(BO_(2))_(2)` (blue) `+C to 2CuBO_(2)` (colourless) `+B_(2)O_(3) + CO`
`2Cu(BO_(2))_(2) + 2C to 2Cu` (red and opaque) `+2B_(2)O_(3) +2CO`
(ii)`AgBr+ 2NH_(3) to [Ag(NH_(3))_(2)] Br`
(iii)`2Cr(OH)_(3) + 2Na_(2)CO_(3) + 3KNO_(3) overset("fused") to 2Na_(2)CrO_(4) +3KNO_(2) +2CO_(2) + 3H_(2)O`
(iv)`2Cu(NO_(3))_(2) to 2 CuO +4NO_(2) +O_(2)`