Synthesis

Reaction balancer

Exact integer coefficients by rational null-space. Unbalanceable input is flagged, never fudged.

element-conservation null space
Use "=" or "->". Ions balance too: write charges as Na+, Cl-, Ca2+, SO4^2-, or Cu++. Charge is conserved alongside mass; input coefficients are ignored.
Reaction balancer, Aliquot