Response:
The specific heat of the alloy 
Clarification:
Weight of the alloy
= 25 gm
Initial temperature
= 100°c = 373 K
Weight of the water
= 90 gm
Initial temperature of water
= 25.32 °c = 298.32 K
Final temperature
= 27.18 °c = 300.18 K
Using the energy balance equation,
Heat released by the alloy = Heat absorbed by the water
[[
-
] =
(
-
)
25 ×
× ( 373 - 300.18 ) = 90 × 4.2 (300.18 - 298.32)

This gives us the specific heat of the alloy.
The balanced equation is:
NaCH₃COO + HCl → NaCl + HCH₃COO
Make
Let's represent molecules with symbols as follows:
C₂O₄ = X
and
H₂O = Y
Then,
K [ Co (X)₂ (Y)₂ ]
Since Potassium (K) has an oxidation number of +1
To achieve neutrality, the oxidation number of the coordination sphere needs to equal -1.
Thus,
[ Co (X)₂ (Y)₂ ] = -1
Given that,
the O.N of X is -2
Therefore,
O.N of (X)₂ equals -4
Additionally,
O.N of H₂O is zero since it remains neutral. Therefore,
[Co - 4 + 0 ] = -1
Or,
Co = -1 + 4
Co = +3
Conclusion:
The oxidation number for the coordination sphere is -1, and the oxidation state of copper is +3.