First, we write the reaction equation:
NiCO₃ + 2HBr → NiBr₂ + H₂CO₃
Now, writing this in ionic form:
NiCO₃ + 2H⁺ + 2Br⁻ → NiBr₂ + 2H⁺ + CO₃⁻²
(NiCO₃ is insoluble so it does not dissociate in to ions very readily)
Overall equation:
NiCO₃ + 2Br⁻ → NiBr₂ + CO₃⁻²
Answer : The balanced two-half reactions will be,
Oxidation half reaction : 
Reduction half reaction : 
Explanation :
Voltaic cell : It is defined as a device which is used for the conversion of the chemical energy produces in a redox reaction into the electrical energy. It is also known as the galvanic cell or electrochemical cell.
In the voltaic cell, the oxidation occurs at an anode which is a negative electrode and the reduction occurs at the cathode which is a positive electrode.
The given redox reaction is:

The balanced two-half reactions will be,
Oxidation half reaction : 
Reduction half reaction : 
All of these metals from cations, so they lost electrons when forming ions. The answer is D.
Answer:
HI (hydrogen iodide).
Explanation:
Hello,
In this case, since iodine is in group VIIA, it has seven valence electrons at its outer shell, which means that it only needs one bond to attain the octet. Moreover, since hydrogen has just one electron at its outer shell, one hydrogen turns out enough to obey the octet when hydrogen and iodine bond as shown below:

Therefore, the required formula is:

Which is hydrogen iodide.
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Answer:
is what a model answer key