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Answer:
Hello there Dude answer is B :D hope it helped mark me brainliest.
The formula of the compound formed has been [tex]\rm \bold {K_2O}[/tex]. Thus, option D is correct.
The sample of potassium has mass of 0.242 g. Since, the substance has been heated in the presence of oxygen, the gain in the weight has been corresponds with the mass of oxygen.
The given sample has:
Mass of potassium, [tex]m_K=0.242\;\text g[/tex]
Mass of heated sample, [tex]m_S=0.292\;\text g[/tex]
The mass of oxygen ([tex]m_O[/tex]) in the sample has been given as:
[tex]m_O=m_S-m_K[/tex]
Substituting the values:
[tex]m_O=0.292\;-\;0.242\;\text g\\m_O=0.05\;\text g[/tex]
The mass of oxygen in the sample has been 0.05 g.
The moles (M) of compounds in the sample has been given as:
[tex]M=\dfrac{m}{mwt}[/tex]
Where, m has been the mass of the compound, and
mwt has been the molecular weight of the compound.
The moles of potassium ([tex]M_K[/tex]) has been given as:
[tex]M_K=\dfrac{0.242}{39.098}\\M_K=0.006\;\text mol[/tex]
The moles of oxygen ([tex]M_O[/tex]) has been given as:
[tex]M_O=\dfrac{0.05}{16}\\M_O=0.003\;\text mol[/tex]
The molecular compound has been formed with Potassium and oxygen in the ratio of their moles as:
[tex]\rm \dfrac{K}{O}=\dfrac{0.006}{0.003}\\ \dfrac{K}{O}= \dfrac{2}1}[/tex]
Thus, the molecular formula of the compound has been [tex]\rm \bold {K_2O}[/tex]. Thus, option D is correct.
For more information about molecular formula, refer to the link:
https://brainly.com/question/1247523