What does below chemistry rebus means?

When can we add 2 to 11 and get 1 as the correct answer?

What is the next number in this matchsticks series riddle?

In the Mexico City area, there are two Houses H1 and H2. Both H1 and H2 have two children each.
In House H1, The boy plays for Mexico Youth academy and the other child plays baseball.
In House H2, The boy Plays soccer for his school in Mexico and they recently have a newborn.

Can you prove that the probability of House-H1 having a girl child is more than that of House-H2?

Why do you find that most of the buildings are deprived of the 13th floor?

You see me once in June, twice in November, and not at all in May. What am I?

Why is the longest human nose just 11 inches?

Find the smallest sentence with all the English alphabet.

In an office's desk, you find a unique method that shows the current day of the month. Two numbered cubes are used to depict the current date.

Can you find out the numbers on both the cubes so that each date can be mentioned using them?

Please note that you have to use both the cubes to display any date. Thus the 1st day must be represented by 01 and so on.

I welcome the day with a show of light, I stealthily came here in the night. I bathe the earthy stuff at dawn, But by noon, alas! I'm gone.