An element has two main isotopes of mass numbers $85$ and $87$. In nature,they occur in the ratio of $75\%$ and $25\%$ respectively. The atomic weight of the element will be approximately:

$1.5 \ g$ of $CdCl_2$ was found to contain $0.9 \ g$ of $Cd$. Calculate the atomic weight of $Cd$.

When $1.0 \ g$ of a metal nitrate is converted into $0.86 \ g$ of metal sulfate,what is the equivalent weight of the metal?

The equivalent mass of a divalent metal is $32$. What is the molar mass of its nitrate salt?

Chlorine has two isotopes $^{35}Cl$ and $^{37}Cl$ with an average atomic mass of $35.5$. What is the ratio of their relative abundance respectively?

Naturally occurring boron consists of two isotopes with atomic masses $10.01 \ (I)$ and $11.01 \ (II)$. The average atomic mass of natural boron is $10.81$. Find the percentage abundance of isotopes $(I)$ and $(II)$ respectively.