Force is a strength or energy as an attribute or physical action or movement, motion is the action or process of moving or being moved
#AB
Electronegativity difference=3.3-2.9=0.4.
- It's a covalent bond.
- Gaseous or solid substance.
#AC
Electronegativity difference=3.3-0.7=2.6
- Its an ionic bond.
- Solid substance.
#BC
Electronegativity difference=2.9-0.7=2.3
- It's an ionic bond
- Solid substance
To do this problem it is necessary to take into account that the heat given by the unknown substance is equal to the heat absorbed by the water, but considering the correct sign:

Clearing the specific heat of the unknown substance:

D only..
A is pure compound
B is mixture of compound and element
C is mixture of compounds
D is mixture of elements