The correct option is C 3.011×1026
We know that,
1 mole of KClO3 formula units contain
=6.022×1023 formula units of KClO3
Therefore,
0.5 kilomoles of KClO3 formula units contain
=0.5×103×6.022×1023 formula units of KClO3
=3.011×1026 formula units of KClO3