In a certain code language, ‘SHOES’ is written as ‘19815519’, ‘SEED’ is written as ‘19554’. What is the code for ‘CHAIR’ in that code language?

number corresponding to the letter of the alphabet 

 $$\left[S\right]    \rightarrow    \left(19 \right)$$

 $$\left[H\right]    \rightarrow    \left(8 \right)$$
 $$\left[O\right]    \rightarrow    \left(15 \right)$$
 $$\left[E\right]    \rightarrow    \left(5 \right)$$
 $$\left[S\right]    \rightarrow    \left(19 \right)$$

"SHOES" $$ \rightarrow  $$"19815519"

similarly 

$$\left[S\right]    \rightarrow    \left(19 \right)$$

 $$\left[E\right]    \rightarrow    \left(5 \right)$$  

$$\left[E\right]    \rightarrow    \left(5 \right)$$  

$$\left[D\right]    \rightarrow    \left(4 \right)$$

"SEED" $$ \rightarrow  $$"19554"

similarly "CHAIR"  $$ \rightarrow  $$ "381918"