It seems that you have missed the necessary options for us to answer this question, but anyway here is the answer. William adds two values, following the rules for using significant figures in computations. He should write the sum of these two numbers by using the same number of decimal places as the least precise value. Hope this helps.
Covalent bonds do not involve electron transfer because in covalent bonds, the electrons are shared between the atoms to form the molecule rather than being transferred to form ions as it is in the case of ionic bonds.<span />
Answer:
Concentration of product at equilibrium ;
![[H^+]=0.0000229 M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D0.0000229%20M)
![[CN^-]=0.0000229 M](https://tex.z-dn.net/?f=%5BCN%5E-%5D%3D0.0000229%20M)
Explanation:

initially
0.85 M 0 0
(0.85-x)M x x
The equilibrium constant of reaction = 
The expression of an equilibrium cannot can be written as:
![K_c=\frac{[H^+][CN^-]}{[HCN]}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BH%5E%2B%5D%5BCN%5E-%5D%7D%7B%5BHCN%5D%7D)

Solving for x:
x = 0.0000229
Concentration of product at equilibrium ;
![[H^+]=0.0000229 M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D0.0000229%20M)
![[CN^-]=0.0000229 M](https://tex.z-dn.net/?f=%5BCN%5E-%5D%3D0.0000229%20M)
<span> ester of Ethanol and Ethanoic Acid is Ethyl Ethanoate. </span>
<span><span><span><span><span><span><span><span>C</span></span></span><span><span><span>2</span></span></span></span><span><span><span><span>H</span></span></span><span><span><span>5</span></span></span></span><span><span>O</span></span><span><span>H</span></span><span><span>(</span></span><span><span>l</span></span><span><span>)</span></span><span><span>+</span></span><span><span>C</span></span><span><span><span><span>H</span></span></span><span><span><span>3</span></span></span></span><span><span>C</span></span><span><span>O</span></span><span><span>O</span></span><span><span>H</span></span><span><span>(</span></span><span><span>l</span></span><span><span>)</span></span><span><span><span><span><span><span><span><span><span>c</span></span><span><span>o</span></span><span><span>n</span></span><span><span>c</span></span><span><span>.</span></span><span><span><span><span>H</span></span></span><span><span><span>2</span></span></span></span><span><span>S</span></span><span><span><span><span>O</span></span></span><span><span><span>4</span></span></span></span><span><span><span><span>/</span></span></span></span><span><span>w</span></span><span><span>a</span></span><span><span>r</span></span><span><span>m</span></span></span></span><span /></span></span></span><span><span><span><span>−</span><span>−−−−−−−−−−</span><span>→</span></span></span></span></span></span><span><span>C</span></span><span><span><span><span>H</span></span></span><span><span><span>3</span></span></span></span><span><span>C</span></span><span><span>O</span></span><span><span>O</span></span><span><span>C</span></span><span><span><span><span>H</span></span></span><span><span><span>2</span></span></span></span><span><span>C</span></span><span><span><span><span>H</span></span></span><span><span><span>3</span></span></span></span><span><span>(</span></span><span><span>a</span></span><span><span>q</span></span><span><span>)</span></span><span><span>+</span></span><span><span><span><span>H</span></span></span><span><span><span>2</span></span></span></span><span><span>O</span></span><span><span>(</span></span><span><span>l</span></span><span><span>)</span></span></span></span><span>C2H5OH(l)+CH3COOH(l)→conc.H2SO4/warmCH3COOCH2CH3(aq)+H2O(l)</span></span></span>
<span><span><span><span><span><span>Condition: Warm con. reactants with conc.</span></span></span></span><span>Condition: Warm con. reactants with conc.</span></span></span><span><span><span><span><span><span><span><span>H</span></span></span><span><span><span>2</span></span></span></span><span><span>S</span></span><span><span><span><span>O</span></span></span><span><span><span>4</span></span></span></span></span></span><span>H2SO4</span></span></span>
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