tRNA is called soluble RNA since it remains soluble in aqueous solutions. For example, it is soluble in 1M NaCl. tRNA is found within the cytoplasm of the cell, where it's dispersed or dissolved in the intracellular fluid. Thus, it's not bound within cellular structures, allowing it to have the ability to move about freely. This mobility is essential for its primary role of transferring amino acids during the process of protein synthesis.